[clang] [Sema] Warning for _Float16 passed to format specifier '%f' (PR #74439)

2023-12-05 Thread Haocong Lu via cfe-commits 

https://github.com/Luhaocong created 
https://github.com/llvm/llvm-project/pull/74439

According to https://www.open-std.org/jtc1/sc22/wg14/www/docs/n2844.pdf, 
default argument promotions for _FloatN types has been removed.

A warning is needed to notice user to promote _Float16 to double explicitly, 
and then pass it to format specifier '%f', which is consistent with GCC.

Fixes: https://github.com/llvm/llvm-project/issues/68538

>From 10c48f5c8c50617929cc72401721afc379131346 Mon Sep 17 00:00:00 2001
From: Lu Haocong 
Date: Tue, 5 Dec 2023 16:45:22 +0800
Subject: [PATCH] [Sema] Warning for _Float16 passed to format specifier '%f'

According to https://www.open-std.org/jtc1/sc22/wg14/www/docs/n2844.pdf,
default argument promotions for _FloatN types has been removed.

A warning is needed to notice user to promote _Float16 to double
explicitly, and then pass it to format specifier '%f', which is
consistent with GCC.
---
 clang/lib/AST/FormatString.cpp  |  1 -
 clang/test/AST/variadic-promotion.c |  5 +
 clang/test/Sema/attr-format.c   |  7 +++
 clang/test/SemaCXX/attr-format.cpp  |  1 +
 clang/test/SemaCXX/format-strings-scanf.cpp | 16 ++--
 5 files changed, 23 insertions(+), 7 deletions(-)

diff --git a/clang/lib/AST/FormatString.cpp b/clang/lib/AST/FormatString.cpp
index e0c9e18cfe3a2..c5d14b4af7ff1 100644
--- a/clang/lib/AST/FormatString.cpp
+++ b/clang/lib/AST/FormatString.cpp
@@ -488,7 +488,6 @@ ArgType::matchesType(ASTContext &C, QualType argTy) const {
 return NoMatchPromotionTypeConfusion;
   break;
 case BuiltinType::Half:
-case BuiltinType::Float16:
 case BuiltinType::Float:
   if (T == C.DoubleTy)
 return MatchPromotion;
diff --git a/clang/test/AST/variadic-promotion.c 
b/clang/test/AST/variadic-promotion.c
index 41c7fec8d7943..7cbadb832ca80 100644
--- a/clang/test/AST/variadic-promotion.c
+++ b/clang/test/AST/variadic-promotion.c
@@ -18,3 +18,8 @@ void test_floating_promotion(__fp16 *f16, float f32, double 
f64) {
 // CHECK: ImplicitCastExpr {{.*}} 'double' 
 // CHECK-NEXT: 'float'
 }
+
+void test_Float16_no_default_promotion(_Float16 f16) {
+  variadic(1, f16);
+// CHECK-NOT: ImplicitCastExpr {{.*}} 'double' 
+}
diff --git a/clang/test/Sema/attr-format.c b/clang/test/Sema/attr-format.c
index 1f4c864d4f78b..bdfd8425c4e9a 100644
--- a/clang/test/Sema/attr-format.c
+++ b/clang/test/Sema/attr-format.c
@@ -16,6 +16,8 @@ typedef const char *xpto;
 void j(xpto c, va_list list) __attribute__((format(printf, 1, 0))); // no-error
 void k(xpto c) __attribute__((format(printf, 1, 0)));   // no-error
 
+void l(char *a, _Float16 b) __attribute__((format(printf, 1, 2))); // 
expected-warning {{GCC requires a function with the 'format' attribute to be 
variadic}}
+
 void y(char *str) __attribute__((format(strftime, 1, 0))); // 
no-error
 void z(char *str, int c, ...) __attribute__((format(strftime, 1, 2))); // 
expected-error {{strftime format attribute requires 3rd parameter to be 0}}
 
@@ -93,6 +95,11 @@ void call_nonvariadic(void) {
   d3("%s", 123); // expected-warning{{format specifies type 'char *' but the 
argument has type 'int'}}
 }
 
+void call_no_default_promotion(void) {
+  a("%f", (_Float16)1.0); // expected-warning{{format specifies type 'double' 
but the argument has type '_Float16'}}
+  l("%f", (_Float16)1.0); // expected-warning{{format specifies type 'double' 
but the argument has type '_Float16'}}
+}
+
 __attribute__((format(printf, 1, 2)))
 void forward_fixed(const char *fmt, _Bool b, char i, short j, int k, float l, 
double m) { // expected-warning{{GCC requires a function with the 'format' 
attribute to be variadic}}
   forward_fixed(fmt, b, i, j, k, l, m);
diff --git a/clang/test/SemaCXX/attr-format.cpp 
b/clang/test/SemaCXX/attr-format.cpp
index adc05fc46776c..4509c3a95e8ef 100644
--- a/clang/test/SemaCXX/attr-format.cpp
+++ b/clang/test/SemaCXX/attr-format.cpp
@@ -81,6 +81,7 @@ void do_format() {
 
   format("%c %c %hhd %hd %d\n", (char)'a', 'a', 'a', (short)123, (int)123);
   format("%f %f %f\n", (__fp16)123.f, 123.f, 123.);
+  format("%f", (_Float16)123.f);// expected-warning{{format specifies type 
'double' but the argument has type '_Float16'}}
   format("%Lf", (__fp16)123.f); // expected-warning{{format specifies type 
'long double' but the argument has type '__fp16'}}
   format("%Lf", 123.f); // expected-warning{{format specifies type 'long 
double' but the argument has type 'float'}}
   format("%hhi %hhu %hi %hu %i %u", b, b, b, b, b, b);
diff --git a/clang/test/SemaCXX/format-strings-scanf.cpp 
b/clang/test/SemaCXX/format-strings-scanf.cpp
index 25fe5346791a0..406c2069e28ca 100644
--- a/clang/test/SemaCXX/format-strings-scanf.cpp
+++ b/clang/test/SemaCXX/format-strings-scanf.cpp
@@ -22,6 +22,7 @@ union bag {
 unsigned long long ull;
 signed long long sll;
 __fp16 f16;
+_Float16 Float16;

[clang] [Sema] Warning for _Float16 passed to format specifier '%f' (PR #74439)

2023-12-05 Thread Haocong Lu via cfe-commits 

https://github.com/Luhaocong updated 
https://github.com/llvm/llvm-project/pull/74439

>From afb0d3909cde31cf73e2baf3efd13d584943704f Mon Sep 17 00:00:00 2001
From: Lu Haocong 
Date: Tue, 5 Dec 2023 16:45:22 +0800
Subject: [PATCH] [Sema] Warning for _Float16 passed to format specifier '%f'

According to https://www.open-std.org/jtc1/sc22/wg14/www/docs/n2844.pdf,
default argument promotions for _FloatN types has been removed.

A warning is needed to notice user to promote _Float16 to double
explicitly, and then pass it to format specifier '%f', which is
consistent with GCC.
---
 clang/lib/AST/FormatString.cpp  |  1 -
 clang/test/AST/variadic-promotion.c |  5 +
 clang/test/Sema/attr-format.c   |  7 +++
 clang/test/SemaCXX/attr-format.cpp  |  1 +
 clang/test/SemaCXX/format-strings-scanf.cpp | 16 ++--
 5 files changed, 23 insertions(+), 7 deletions(-)

diff --git a/clang/lib/AST/FormatString.cpp b/clang/lib/AST/FormatString.cpp
index e0c9e18cfe3a2..c5d14b4af7ff1 100644
--- a/clang/lib/AST/FormatString.cpp
+++ b/clang/lib/AST/FormatString.cpp
@@ -488,7 +488,6 @@ ArgType::matchesType(ASTContext &C, QualType argTy) const {
 return NoMatchPromotionTypeConfusion;
   break;
 case BuiltinType::Half:
-case BuiltinType::Float16:
 case BuiltinType::Float:
   if (T == C.DoubleTy)
 return MatchPromotion;
diff --git a/clang/test/AST/variadic-promotion.c 
b/clang/test/AST/variadic-promotion.c
index 41c7fec8d7943..7cbadb832ca80 100644
--- a/clang/test/AST/variadic-promotion.c
+++ b/clang/test/AST/variadic-promotion.c
@@ -18,3 +18,8 @@ void test_floating_promotion(__fp16 *f16, float f32, double 
f64) {
 // CHECK: ImplicitCastExpr {{.*}} 'double' 
 // CHECK-NEXT: 'float'
 }
+
+void test_Float16_no_default_promotion(_Float16 f16) {
+  variadic(1, f16);
+// CHECK-NOT: ImplicitCastExpr {{.*}} 'double' 
+}
diff --git a/clang/test/Sema/attr-format.c b/clang/test/Sema/attr-format.c
index 1f4c864d4f78b..bdfd8425c4e9a 100644
--- a/clang/test/Sema/attr-format.c
+++ b/clang/test/Sema/attr-format.c
@@ -16,6 +16,8 @@ typedef const char *xpto;
 void j(xpto c, va_list list) __attribute__((format(printf, 1, 0))); // no-error
 void k(xpto c) __attribute__((format(printf, 1, 0)));   // no-error
 
+void l(char *a, _Float16 b) __attribute__((format(printf, 1, 2))); // 
expected-warning {{GCC requires a function with the 'format' attribute to be 
variadic}}
+
 void y(char *str) __attribute__((format(strftime, 1, 0))); // 
no-error
 void z(char *str, int c, ...) __attribute__((format(strftime, 1, 2))); // 
expected-error {{strftime format attribute requires 3rd parameter to be 0}}
 
@@ -93,6 +95,11 @@ void call_nonvariadic(void) {
   d3("%s", 123); // expected-warning{{format specifies type 'char *' but the 
argument has type 'int'}}
 }
 
+void call_no_default_promotion(void) {
+  a("%f", (_Float16)1.0); // expected-warning{{format specifies type 'double' 
but the argument has type '_Float16'}}
+  l("%f", (_Float16)1.0); // expected-warning{{format specifies type 'double' 
but the argument has type '_Float16'}}
+}
+
 __attribute__((format(printf, 1, 2)))
 void forward_fixed(const char *fmt, _Bool b, char i, short j, int k, float l, 
double m) { // expected-warning{{GCC requires a function with the 'format' 
attribute to be variadic}}
   forward_fixed(fmt, b, i, j, k, l, m);
diff --git a/clang/test/SemaCXX/attr-format.cpp 
b/clang/test/SemaCXX/attr-format.cpp
index adc05fc46776c..4509c3a95e8ef 100644
--- a/clang/test/SemaCXX/attr-format.cpp
+++ b/clang/test/SemaCXX/attr-format.cpp
@@ -81,6 +81,7 @@ void do_format() {
 
   format("%c %c %hhd %hd %d\n", (char)'a', 'a', 'a', (short)123, (int)123);
   format("%f %f %f\n", (__fp16)123.f, 123.f, 123.);
+  format("%f", (_Float16)123.f);// expected-warning{{format specifies type 
'double' but the argument has type '_Float16'}}
   format("%Lf", (__fp16)123.f); // expected-warning{{format specifies type 
'long double' but the argument has type '__fp16'}}
   format("%Lf", 123.f); // expected-warning{{format specifies type 'long 
double' but the argument has type 'float'}}
   format("%hhi %hhu %hi %hu %i %u", b, b, b, b, b, b);
diff --git a/clang/test/SemaCXX/format-strings-scanf.cpp 
b/clang/test/SemaCXX/format-strings-scanf.cpp
index 25fe5346791a0..406c2069e28ca 100644
--- a/clang/test/SemaCXX/format-strings-scanf.cpp
+++ b/clang/test/SemaCXX/format-strings-scanf.cpp
@@ -22,6 +22,7 @@ union bag {
 unsigned long long ull;
 signed long long sll;
 __fp16 f16;
+_Float16 Float16;
 float ff;
 double fd;
 long double fl;
@@ -51,18 +52,21 @@ void test(void) {
 // expected-warning@+1{{format specifies type 'int *' but the argument has 
type 'short *'}}
 scan("%hhi %i %li", &b.ss, &b.ss, &b.ss);
 
-// expected-warning@+3{{format specifies type 'float *' but the argument 
has type '__fp16 *'}}
+// expe

[clang] [Sema] Warning for _Float16 passed to format specifier '%f' (PR #74439)

2023-12-05 Thread Haocong Lu via cfe-commits 

Luhaocong wrote:

This patch improves implement 
https://github.com/llvm/llvm-project/commit/04e6178ae932c9a1d939dcfe3ef1189f4bbb21aa.
 Could you please help me review this patch @apple-fcloutier @AaronBallman 

https://github.com/llvm/llvm-project/pull/74439
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[clang] [Sema] Warning for _Float16 passed to format specifier '%f' (PR #74439)

2023-12-05 Thread Haocong Lu via cfe-commits 

Luhaocong wrote:

> Should this only apply in C23 mode? Standard behavior until C23 is that 
> `_Float16` promotes to `double`. What about C++?

It seems clang never support default argument promotions for _Float16, as 
described in 
https://github.com/llvm/llvm-project/blob/main/clang/docs/LanguageExtensions.rst#id68
 five years ago. Is there any demand to support this in old C/C++ standard？

And I try case with -std=c99 (https://godbolt.org/z/xqx8e6oh5) and -std=c++11 
(https://godbolt.org/z/Mrn779Tdq) , GCC give a warning at both.

https://github.com/llvm/llvm-project/pull/74439
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[clang] [Sema] Warning for _Float16 passed to format specifier '%f' (PR #74439)

2023-12-06 Thread Haocong Lu via cfe-commits 

https://github.com/Luhaocong updated 
https://github.com/llvm/llvm-project/pull/74439

>From 47ec17023ebc75a61951930b77e08bb2f726775b Mon Sep 17 00:00:00 2001
From: Lu Haocong 
Date: Tue, 5 Dec 2023 16:45:22 +0800
Subject: [PATCH] [Sema] Warning for _Float16 passed to format specifier '%f'

According to https://www.open-std.org/jtc1/sc22/wg14/www/docs/n2844.pdf,
default argument promotions for _FloatN types has been removed.

A warning is needed to notice user to promote _Float16 to double
explicitly, and then pass it to format specifier '%f', which is
consistent with GCC.
---
 clang/lib/AST/FormatString.cpp  |  1 -
 clang/test/AST/variadic-promotion.c |  5 +
 clang/test/Sema/attr-format.c   |  7 +++
 clang/test/SemaCXX/attr-format.cpp  |  1 +
 clang/test/SemaCXX/format-strings-scanf.cpp | 16 ++--
 5 files changed, 23 insertions(+), 7 deletions(-)

diff --git a/clang/lib/AST/FormatString.cpp b/clang/lib/AST/FormatString.cpp
index e0c9e18cfe3a2..c5d14b4af7ff1 100644
--- a/clang/lib/AST/FormatString.cpp
+++ b/clang/lib/AST/FormatString.cpp
@@ -488,7 +488,6 @@ ArgType::matchesType(ASTContext &C, QualType argTy) const {
 return NoMatchPromotionTypeConfusion;
   break;
 case BuiltinType::Half:
-case BuiltinType::Float16:
 case BuiltinType::Float:
   if (T == C.DoubleTy)
 return MatchPromotion;
diff --git a/clang/test/AST/variadic-promotion.c 
b/clang/test/AST/variadic-promotion.c
index 41c7fec8d7943..7cbadb832ca80 100644
--- a/clang/test/AST/variadic-promotion.c
+++ b/clang/test/AST/variadic-promotion.c
@@ -18,3 +18,8 @@ void test_floating_promotion(__fp16 *f16, float f32, double 
f64) {
 // CHECK: ImplicitCastExpr {{.*}} 'double' 
 // CHECK-NEXT: 'float'
 }
+
+void test_Float16_no_default_promotion(_Float16 f16) {
+  variadic(1, f16);
+// CHECK-NOT: ImplicitCastExpr {{.*}} 'double' 
+}
diff --git a/clang/test/Sema/attr-format.c b/clang/test/Sema/attr-format.c
index 1f4c864d4f78b..bdfd8425c4e9a 100644
--- a/clang/test/Sema/attr-format.c
+++ b/clang/test/Sema/attr-format.c
@@ -16,6 +16,8 @@ typedef const char *xpto;
 void j(xpto c, va_list list) __attribute__((format(printf, 1, 0))); // no-error
 void k(xpto c) __attribute__((format(printf, 1, 0)));   // no-error
 
+void l(char *a, _Float16 b) __attribute__((format(printf, 1, 2))); // 
expected-warning {{GCC requires a function with the 'format' attribute to be 
variadic}}
+
 void y(char *str) __attribute__((format(strftime, 1, 0))); // 
no-error
 void z(char *str, int c, ...) __attribute__((format(strftime, 1, 2))); // 
expected-error {{strftime format attribute requires 3rd parameter to be 0}}
 
@@ -93,6 +95,11 @@ void call_nonvariadic(void) {
   d3("%s", 123); // expected-warning{{format specifies type 'char *' but the 
argument has type 'int'}}
 }
 
+void call_no_default_promotion(void) {
+  a("%f", (_Float16)1.0); // expected-warning{{format specifies type 'double' 
but the argument has type '_Float16'}}
+  l("%f", (_Float16)1.0); // expected-warning{{format specifies type 'double' 
but the argument has type '_Float16'}}
+}
+
 __attribute__((format(printf, 1, 2)))
 void forward_fixed(const char *fmt, _Bool b, char i, short j, int k, float l, 
double m) { // expected-warning{{GCC requires a function with the 'format' 
attribute to be variadic}}
   forward_fixed(fmt, b, i, j, k, l, m);
diff --git a/clang/test/SemaCXX/attr-format.cpp 
b/clang/test/SemaCXX/attr-format.cpp
index adc05fc46776c..4509c3a95e8ef 100644
--- a/clang/test/SemaCXX/attr-format.cpp
+++ b/clang/test/SemaCXX/attr-format.cpp
@@ -81,6 +81,7 @@ void do_format() {
 
   format("%c %c %hhd %hd %d\n", (char)'a', 'a', 'a', (short)123, (int)123);
   format("%f %f %f\n", (__fp16)123.f, 123.f, 123.);
+  format("%f", (_Float16)123.f);// expected-warning{{format specifies type 
'double' but the argument has type '_Float16'}}
   format("%Lf", (__fp16)123.f); // expected-warning{{format specifies type 
'long double' but the argument has type '__fp16'}}
   format("%Lf", 123.f); // expected-warning{{format specifies type 'long 
double' but the argument has type 'float'}}
   format("%hhi %hhu %hi %hu %i %u", b, b, b, b, b, b);
diff --git a/clang/test/SemaCXX/format-strings-scanf.cpp 
b/clang/test/SemaCXX/format-strings-scanf.cpp
index 25fe5346791a0..406c2069e28ca 100644
--- a/clang/test/SemaCXX/format-strings-scanf.cpp
+++ b/clang/test/SemaCXX/format-strings-scanf.cpp
@@ -22,6 +22,7 @@ union bag {
 unsigned long long ull;
 signed long long sll;
 __fp16 f16;
+_Float16 Float16;
 float ff;
 double fd;
 long double fl;
@@ -51,18 +52,21 @@ void test(void) {
 // expected-warning@+1{{format specifies type 'int *' but the argument has 
type 'short *'}}
 scan("%hhi %i %li", &b.ss, &b.ss, &b.ss);
 
-// expected-warning@+3{{format specifies type 'float *' but the argument 
has type '__fp16 *'}}
+// expe

[clang] [Sema] Warning for _Float16 passed to format specifier '%f' (PR #74439)

2024-01-04 Thread Haocong Lu via cfe-commits 

https://github.com/Luhaocong updated 
https://github.com/llvm/llvm-project/pull/74439

>From 899e18d1ca94efad41c2e09dff0a3213d7fb0f7e Mon Sep 17 00:00:00 2001
From: Lu Haocong 
Date: Tue, 5 Dec 2023 16:45:22 +0800
Subject: [PATCH] [Sema] Warning for _Float16 passed to format specifier '%f'

According to https://www.open-std.org/jtc1/sc22/wg14/www/docs/n2844.pdf,
there are no default argument promotions for _FloatN types.

A warning is needed to notice user to promote _Float16 to double
explicitly, and then pass it to format specifier '%f', which is
consistent with GCC.
---
 clang/lib/AST/FormatString.cpp  |  1 -
 clang/test/AST/variadic-promotion.c |  5 +
 clang/test/Sema/attr-format.c   |  7 +++
 clang/test/SemaCXX/attr-format.cpp  |  1 +
 clang/test/SemaCXX/format-strings-scanf.cpp | 16 ++--
 5 files changed, 23 insertions(+), 7 deletions(-)

diff --git a/clang/lib/AST/FormatString.cpp b/clang/lib/AST/FormatString.cpp
index e0c9e18cfe3a24..c5d14b4af7ff15 100644
--- a/clang/lib/AST/FormatString.cpp
+++ b/clang/lib/AST/FormatString.cpp
@@ -488,7 +488,6 @@ ArgType::matchesType(ASTContext &C, QualType argTy) const {
 return NoMatchPromotionTypeConfusion;
   break;
 case BuiltinType::Half:
-case BuiltinType::Float16:
 case BuiltinType::Float:
   if (T == C.DoubleTy)
 return MatchPromotion;
diff --git a/clang/test/AST/variadic-promotion.c 
b/clang/test/AST/variadic-promotion.c
index 41c7fec8d7943e..7cbadb832ca806 100644
--- a/clang/test/AST/variadic-promotion.c
+++ b/clang/test/AST/variadic-promotion.c
@@ -18,3 +18,8 @@ void test_floating_promotion(__fp16 *f16, float f32, double 
f64) {
 // CHECK: ImplicitCastExpr {{.*}} 'double' 
 // CHECK-NEXT: 'float'
 }
+
+void test_Float16_no_default_promotion(_Float16 f16) {
+  variadic(1, f16);
+// CHECK-NOT: ImplicitCastExpr {{.*}} 'double' 
+}
diff --git a/clang/test/Sema/attr-format.c b/clang/test/Sema/attr-format.c
index 1f4c864d4f78bd..bdfd8425c4e9a5 100644
--- a/clang/test/Sema/attr-format.c
+++ b/clang/test/Sema/attr-format.c
@@ -16,6 +16,8 @@ typedef const char *xpto;
 void j(xpto c, va_list list) __attribute__((format(printf, 1, 0))); // no-error
 void k(xpto c) __attribute__((format(printf, 1, 0)));   // no-error
 
+void l(char *a, _Float16 b) __attribute__((format(printf, 1, 2))); // 
expected-warning {{GCC requires a function with the 'format' attribute to be 
variadic}}
+
 void y(char *str) __attribute__((format(strftime, 1, 0))); // 
no-error
 void z(char *str, int c, ...) __attribute__((format(strftime, 1, 2))); // 
expected-error {{strftime format attribute requires 3rd parameter to be 0}}
 
@@ -93,6 +95,11 @@ void call_nonvariadic(void) {
   d3("%s", 123); // expected-warning{{format specifies type 'char *' but the 
argument has type 'int'}}
 }
 
+void call_no_default_promotion(void) {
+  a("%f", (_Float16)1.0); // expected-warning{{format specifies type 'double' 
but the argument has type '_Float16'}}
+  l("%f", (_Float16)1.0); // expected-warning{{format specifies type 'double' 
but the argument has type '_Float16'}}
+}
+
 __attribute__((format(printf, 1, 2)))
 void forward_fixed(const char *fmt, _Bool b, char i, short j, int k, float l, 
double m) { // expected-warning{{GCC requires a function with the 'format' 
attribute to be variadic}}
   forward_fixed(fmt, b, i, j, k, l, m);
diff --git a/clang/test/SemaCXX/attr-format.cpp 
b/clang/test/SemaCXX/attr-format.cpp
index adc05fc46776ca..4509c3a95e8efa 100644
--- a/clang/test/SemaCXX/attr-format.cpp
+++ b/clang/test/SemaCXX/attr-format.cpp
@@ -81,6 +81,7 @@ void do_format() {
 
   format("%c %c %hhd %hd %d\n", (char)'a', 'a', 'a', (short)123, (int)123);
   format("%f %f %f\n", (__fp16)123.f, 123.f, 123.);
+  format("%f", (_Float16)123.f);// expected-warning{{format specifies type 
'double' but the argument has type '_Float16'}}
   format("%Lf", (__fp16)123.f); // expected-warning{{format specifies type 
'long double' but the argument has type '__fp16'}}
   format("%Lf", 123.f); // expected-warning{{format specifies type 'long 
double' but the argument has type 'float'}}
   format("%hhi %hhu %hi %hu %i %u", b, b, b, b, b, b);
diff --git a/clang/test/SemaCXX/format-strings-scanf.cpp 
b/clang/test/SemaCXX/format-strings-scanf.cpp
index 25fe5346791a0d..406c2069e28ca7 100644
--- a/clang/test/SemaCXX/format-strings-scanf.cpp
+++ b/clang/test/SemaCXX/format-strings-scanf.cpp
@@ -22,6 +22,7 @@ union bag {
 unsigned long long ull;
 signed long long sll;
 __fp16 f16;
+_Float16 Float16;
 float ff;
 double fd;
 long double fl;
@@ -51,18 +52,21 @@ void test(void) {
 // expected-warning@+1{{format specifies type 'int *' but the argument has 
type 'short *'}}
 scan("%hhi %i %li", &b.ss, &b.ss, &b.ss);
 
-// expected-warning@+3{{format specifies type 'float *' but the argument 
has type '__fp16 *'}}
+/

[clang] [Sema] Warning for _Float16 passed to format specifier '%f' (PR #74439)

2024-01-04 Thread Haocong Lu via cfe-commits 

Luhaocong wrote:

Thanks for everyone's review. Do you have any other suggestions for this 
change, and can this pull request be accepted ?

https://github.com/llvm/llvm-project/pull/74439
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[clang] [Sema] Warning for _Float16 passed to format specifier '%f' (PR #74439)

2024-01-04 Thread Haocong Lu via cfe-commits 

https://github.com/Luhaocong updated 
https://github.com/llvm/llvm-project/pull/74439

>From e86dc461c8654b6b9806ad88bf2ba3d731c81d50 Mon Sep 17 00:00:00 2001
From: Lu Haocong 
Date: Tue, 5 Dec 2023 16:45:22 +0800
Subject: [PATCH] [Sema] Warning for _Float16 passed to format specifier '%f'

According to https://www.open-std.org/jtc1/sc22/wg14/www/docs/n2844.pdf,
there are no default argument promotions for _FloatN types.

A warning is needed to notice user to promote _Float16 to double
explicitly, and then pass it to format specifier '%f', which is
consistent with GCC.
---
 clang/lib/AST/FormatString.cpp  |  1 -
 clang/test/Sema/attr-format.c   |  7 +++
 clang/test/SemaCXX/attr-format.cpp  |  1 +
 clang/test/SemaCXX/format-strings-scanf.cpp | 16 ++--
 4 files changed, 18 insertions(+), 7 deletions(-)

diff --git a/clang/lib/AST/FormatString.cpp b/clang/lib/AST/FormatString.cpp
index e0c9e18cfe3a24..c5d14b4af7ff15 100644
--- a/clang/lib/AST/FormatString.cpp
+++ b/clang/lib/AST/FormatString.cpp
@@ -488,7 +488,6 @@ ArgType::matchesType(ASTContext &C, QualType argTy) const {
 return NoMatchPromotionTypeConfusion;
   break;
 case BuiltinType::Half:
-case BuiltinType::Float16:
 case BuiltinType::Float:
   if (T == C.DoubleTy)
 return MatchPromotion;
diff --git a/clang/test/Sema/attr-format.c b/clang/test/Sema/attr-format.c
index 1f4c864d4f78bd..bdfd8425c4e9a5 100644
--- a/clang/test/Sema/attr-format.c
+++ b/clang/test/Sema/attr-format.c
@@ -16,6 +16,8 @@ typedef const char *xpto;
 void j(xpto c, va_list list) __attribute__((format(printf, 1, 0))); // no-error
 void k(xpto c) __attribute__((format(printf, 1, 0)));   // no-error
 
+void l(char *a, _Float16 b) __attribute__((format(printf, 1, 2))); // 
expected-warning {{GCC requires a function with the 'format' attribute to be 
variadic}}
+
 void y(char *str) __attribute__((format(strftime, 1, 0))); // 
no-error
 void z(char *str, int c, ...) __attribute__((format(strftime, 1, 2))); // 
expected-error {{strftime format attribute requires 3rd parameter to be 0}}
 
@@ -93,6 +95,11 @@ void call_nonvariadic(void) {
   d3("%s", 123); // expected-warning{{format specifies type 'char *' but the 
argument has type 'int'}}
 }
 
+void call_no_default_promotion(void) {
+  a("%f", (_Float16)1.0); // expected-warning{{format specifies type 'double' 
but the argument has type '_Float16'}}
+  l("%f", (_Float16)1.0); // expected-warning{{format specifies type 'double' 
but the argument has type '_Float16'}}
+}
+
 __attribute__((format(printf, 1, 2)))
 void forward_fixed(const char *fmt, _Bool b, char i, short j, int k, float l, 
double m) { // expected-warning{{GCC requires a function with the 'format' 
attribute to be variadic}}
   forward_fixed(fmt, b, i, j, k, l, m);
diff --git a/clang/test/SemaCXX/attr-format.cpp 
b/clang/test/SemaCXX/attr-format.cpp
index adc05fc46776ca..4509c3a95e8efa 100644
--- a/clang/test/SemaCXX/attr-format.cpp
+++ b/clang/test/SemaCXX/attr-format.cpp
@@ -81,6 +81,7 @@ void do_format() {
 
   format("%c %c %hhd %hd %d\n", (char)'a', 'a', 'a', (short)123, (int)123);
   format("%f %f %f\n", (__fp16)123.f, 123.f, 123.);
+  format("%f", (_Float16)123.f);// expected-warning{{format specifies type 
'double' but the argument has type '_Float16'}}
   format("%Lf", (__fp16)123.f); // expected-warning{{format specifies type 
'long double' but the argument has type '__fp16'}}
   format("%Lf", 123.f); // expected-warning{{format specifies type 'long 
double' but the argument has type 'float'}}
   format("%hhi %hhu %hi %hu %i %u", b, b, b, b, b, b);
diff --git a/clang/test/SemaCXX/format-strings-scanf.cpp 
b/clang/test/SemaCXX/format-strings-scanf.cpp
index 25fe5346791a0d..406c2069e28ca7 100644
--- a/clang/test/SemaCXX/format-strings-scanf.cpp
+++ b/clang/test/SemaCXX/format-strings-scanf.cpp
@@ -22,6 +22,7 @@ union bag {
 unsigned long long ull;
 signed long long sll;
 __fp16 f16;
+_Float16 Float16;
 float ff;
 double fd;
 long double fl;
@@ -51,18 +52,21 @@ void test(void) {
 // expected-warning@+1{{format specifies type 'int *' but the argument has 
type 'short *'}}
 scan("%hhi %i %li", &b.ss, &b.ss, &b.ss);
 
-// expected-warning@+3{{format specifies type 'float *' but the argument 
has type '__fp16 *'}}
+// expected-warning@+4{{format specifies type 'float *' but the argument 
has type '__fp16 *'}}
+// expected-warning@+3{{format specifies type 'float *' but the argument 
has type '_Float16 *'}}
 // expected-warning@+2{{format specifies type 'float *' but the argument 
has type 'double *'}}
 // expected-warning@+1{{format specifies type 'float *' but the argument 
has type 'long double *'}}
-scan("%f %f %f", &b.f16, &b.fd, &b.fl);
+scan("%f %f %f %f", &b.f16, &b.Float16, &b.fd, &b.fl);
 
-// expected-warning@+3{{format specifies typ

[clang] [Sema] Warning for _Float16 passed to format specifier '%f' (PR #74439)

2024-01-04 Thread Haocong Lu via cfe-commits 


@@ -18,3 +18,8 @@ void test_floating_promotion(__fp16 *f16, float f32, double 
f64) {
 // CHECK: ImplicitCastExpr {{.*}} 'double' 
 // CHECK-NEXT: 'float'
 }
+
+void test_Float16_no_default_promotion(_Float16 f16) {
+  variadic(1, f16);
+// CHECK-NOT: ImplicitCastExpr {{.*}} 'double' 
+}

Luhaocong wrote:

Done

https://github.com/llvm/llvm-project/pull/74439
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[clang] [Sema] Warning for _Float16 passed to format specifier '%f' (PR #74439)

2024-01-04 Thread Haocong Lu via cfe-commits 

Luhaocong wrote:

> LGTM.
> 
> The format diagnostics are new in Clang 18 and as such we do not need a 
> release note. Correct?

This format diagnostics is existent until 
https://github.com/llvm/llvm-project/commit/04e6178ae932c9a1d939dcfe3ef1189f4bbb21aa
 had been committed. Clang 17.0.1 gives a warning: 
https://godbolt.org/z/xMdK9cETY.


https://github.com/llvm/llvm-project/pull/74439
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[clang] [Sema] Warning for _Float16 passed to format specifier '%f' (PR #74439)

2024-01-04 Thread Haocong Lu via cfe-commits 

Luhaocong wrote:

> Thanks for confirming. Do you need me to merge that for you?

It can't be better, thanks.

https://github.com/llvm/llvm-project/pull/74439
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[clang] [Sema] Warning for _Float16 passed to format specifier '%f' (PR #74439)

2024-01-07 Thread Haocong Lu via cfe-commits 

https://github.com/Luhaocong closed 
https://github.com/llvm/llvm-project/pull/74439
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