kpn created this revision.
kpn added reviewers: cameron.mcinally, craig.topper, andrew.w.kaylor, spatel,
wristow, nemanjai.
Herald added subscribers: cfe-commits, arphaman.
Herald added a project: clang.
kpn added a comment.
This currently triggers a failure in test "Clang :: Misc/warning-flags.c".
Suggestions on how to fix that correctly are welcome.
We currently have strict floating point/constrained floating point enabled for
all targets. Constrained SDAG nodes get converted to the regular ones before
reaching the target layer. In theory this should be fine.
However, the changes are exposed to users through multiple clang options
already in use in the field, and the changes are _completely_ _untested_ on
almost all of our targets. Bugs have already been found, like
"https://bugs.llvm.org/show_bug.cgi?id=45274";.
This patch disables constrained floating point options in clang everywhere
except X86 and SystemZ. A warning will be printed when this happens.
Repository:
rG LLVM Github Monorepo
https://reviews.llvm.org/D80952
Files:
clang/include/clang/Basic/DiagnosticFrontendKinds.td
clang/include/clang/Basic/TargetInfo.h
clang/lib/Basic/TargetInfo.cpp
clang/lib/Basic/Targets/SystemZ.h
clang/lib/Basic/Targets/X86.h
clang/lib/Frontend/CompilerInstance.cpp
clang/test/CodeGen/aarch64-neon-misc-constrained.c
clang/test/CodeGen/aarch64-neon-scalar-x-indexed-elem-constrained.c
clang/test/CodeGen/aarch64-v8.2a-neon-intrinsics-constrained.c
clang/test/CodeGen/arm-neon-directed-rounding-constrained.c
clang/test/CodeGen/arm64-vrnd-constrained.c
clang/test/CodeGen/fp-strictfp.cpp
Index: clang/test/CodeGen/fp-strictfp.cpp
===================================================================
--- /dev/null
+++ clang/test/CodeGen/fp-strictfp.cpp
@@ -0,0 +1,19 @@
+// RUN: %clang_cc1 -triple powerpc64-linux-gnu -frounding-math -ffp-exception-behavior=strict -O2 -verify=rounding,exception -emit-llvm -o - %s | FileCheck %s
+// RUN: %clang_cc1 -triple powerpc64-linux-gnu -ffp-exception-behavior=strict -O2 -verify=exception -emit-llvm -o - %s | FileCheck %s
+// RUN: %clang_cc1 -triple powerpc64-linux-gnu -frounding-math -O2 -verify=rounding -emit-llvm -o - %s | FileCheck %s
+//
+// Verify that constrained intrinsics are not used.
+// As more targets gain support for constrained intrinsics the triple
+// in this test will need to change.
+
+// rounding-warning@* {{overriding currently unsupported rounding mode on this target}}
+// exception-warning@* {{overriding currently unsupported use of floating point exceptions on this target}}
+float fp_precise_1(float a, float b, float c) {
+// CHECK: _Z12fp_precise_1fff
+// CHECK: %[[M:.+]] = fmul fast float{{.*}}
+// CHECK: fadd fast float %[[M]], %c
+#pragma float_control(precise, off)
+ return a * b + c;
+}
+
+
Index: clang/test/CodeGen/arm64-vrnd-constrained.c
===================================================================
--- clang/test/CodeGen/arm64-vrnd-constrained.c
+++ clang/test/CodeGen/arm64-vrnd-constrained.c
@@ -9,6 +9,9 @@
// REQUIRES: aarch64-registered-target
+// Disabled until constrained floating point is implemented for arm64.
+// XFAIL: *
+
#include <arm_neon.h>
float64x2_t rnd5(float64x2_t a) { return vrndq_f64(a); }
Index: clang/test/CodeGen/arm-neon-directed-rounding-constrained.c
===================================================================
--- clang/test/CodeGen/arm-neon-directed-rounding-constrained.c
+++ clang/test/CodeGen/arm-neon-directed-rounding-constrained.c
@@ -32,6 +32,9 @@
// REQUIRES: arm-registered-target,aarch64-registered-target
+// Disabled until constrained floating point is implemented for arm64.
+// XFAIL: *
+
#include <arm_neon.h>
// COMMON-LABEL: test_vrndi_f32
Index: clang/test/CodeGen/aarch64-v8.2a-neon-intrinsics-constrained.c
===================================================================
--- clang/test/CodeGen/aarch64-v8.2a-neon-intrinsics-constrained.c
+++ clang/test/CodeGen/aarch64-v8.2a-neon-intrinsics-constrained.c
@@ -19,6 +19,9 @@
// REQUIRES: aarch64-registered-target
+// Disabled until constrained floating point is implemented for arm64.
+// XFAIL: *
+
#include <arm_neon.h>
// COMMON-LABEL: test_vsqrt_f16
Index: clang/test/CodeGen/aarch64-neon-scalar-x-indexed-elem-constrained.c
===================================================================
--- clang/test/CodeGen/aarch64-neon-scalar-x-indexed-elem-constrained.c
+++ clang/test/CodeGen/aarch64-neon-scalar-x-indexed-elem-constrained.c
@@ -15,6 +15,9 @@
// REQUIRES: aarch64-registered-target
+// Disabled until constrained floating point is implemented for arm64.
+// XFAIL: *
+
// Test new aarch64 intrinsics and types but constrained
#include <arm_neon.h>
Index: clang/test/CodeGen/aarch64-neon-misc-constrained.c
===================================================================
--- clang/test/CodeGen/aarch64-neon-misc-constrained.c
+++ clang/test/CodeGen/aarch64-neon-misc-constrained.c
@@ -15,6 +15,9 @@
// REQUIRES: aarch64-registered-target
+// Disabled until constrained floating point is implemented for arm64.
+// XFAIL: *
+
// Test new aarch64 intrinsics and types but constrained
#include <arm_neon.h>
Index: clang/lib/Frontend/CompilerInstance.cpp
===================================================================
--- clang/lib/Frontend/CompilerInstance.cpp
+++ clang/lib/Frontend/CompilerInstance.cpp
@@ -935,6 +935,19 @@
setAuxTarget(TargetInfo::CreateTargetInfo(getDiagnostics(), TO));
}
+ if (!getTarget().hasStrictFP()) {
+ if (getLangOpts().getFPRoundingMode() !=
+ llvm::RoundingMode::NearestTiesToEven) {
+ getDiagnostics().Report(diag::warn_fe_backend_unsupported_fp_rounding);
+ getLangOpts().setFPRoundingMode(llvm::RoundingMode::NearestTiesToEven);
+ }
+ if (getLangOpts().getFPExceptionMode() != LangOptions::FPE_Ignore) {
+ getDiagnostics().Report(diag::warn_fe_backend_unsupported_fp_exceptions);
+ getLangOpts().setFPExceptionMode(LangOptions::FPE_Ignore);
+ }
+ // FIXME: can we disable FEnvAccess?
+ }
+
// Inform the target of the language options.
//
// FIXME: We shouldn't need to do this, the target should be immutable once
Index: clang/lib/Basic/Targets/X86.h
===================================================================
--- clang/lib/Basic/Targets/X86.h
+++ clang/lib/Basic/Targets/X86.h
@@ -149,6 +149,7 @@
: TargetInfo(Triple) {
LongDoubleFormat = &llvm::APFloat::x87DoubleExtended();
AddrSpaceMap = &X86AddrSpaceMap;
+ HasStrictFP = true;
}
const char *getLongDoubleMangling() const override {
Index: clang/lib/Basic/Targets/SystemZ.h
===================================================================
--- clang/lib/Basic/Targets/SystemZ.h
+++ clang/lib/Basic/Targets/SystemZ.h
@@ -48,6 +48,7 @@
MinGlobalAlign = 16;
resetDataLayout("E-m:e-i1:8:16-i8:8:16-i64:64-f128:64-a:8:16-n32:64");
MaxAtomicPromoteWidth = MaxAtomicInlineWidth = 64;
+ HasStrictFP = true;
}
void getTargetDefines(const LangOptions &Opts,
Index: clang/lib/Basic/TargetInfo.cpp
===================================================================
--- clang/lib/Basic/TargetInfo.cpp
+++ clang/lib/Basic/TargetInfo.cpp
@@ -36,6 +36,7 @@
HasLegalHalfType = false;
HasFloat128 = false;
HasFloat16 = false;
+ HasStrictFP = false;
PointerWidth = PointerAlign = 32;
BoolWidth = BoolAlign = 8;
IntWidth = IntAlign = 32;
Index: clang/include/clang/Basic/TargetInfo.h
===================================================================
--- clang/include/clang/Basic/TargetInfo.h
+++ clang/include/clang/Basic/TargetInfo.h
@@ -188,6 +188,7 @@
// LLVM IR type.
bool HasFloat128;
bool HasFloat16;
+ bool HasStrictFP;
unsigned char MaxAtomicPromoteWidth, MaxAtomicInlineWidth;
unsigned short SimdDefaultAlign;
@@ -567,6 +568,9 @@
/// Determine whether the _Float16 type is supported on this target.
virtual bool hasFloat16Type() const { return HasFloat16; }
+ /// Determine whether constrained floating point is supported on this target.
+ virtual bool hasStrictFP() const { return HasStrictFP; }
+
/// Return the alignment that is suitable for storing any
/// object with a fundamental alignment requirement.
unsigned getSuitableAlign() const { return SuitableAlign; }
Index: clang/include/clang/Basic/DiagnosticFrontendKinds.td
===================================================================
--- clang/include/clang/Basic/DiagnosticFrontendKinds.td
+++ clang/include/clang/Basic/DiagnosticFrontendKinds.td
@@ -37,6 +37,11 @@
def warn_fe_override_module : Warning<
"overriding the module target triple with %0">,
InGroup<DiagGroup<"override-module">>;
+def warn_fe_backend_unsupported_fp_rounding : Warning<
+ "overriding currently unsupported rounding mode on this target">;
+def warn_fe_backend_unsupported_fp_exceptions : Warning<
+ "overriding currently unsupported use of floating point exceptions "
+ "on this target">;
def remark_fe_backend_optimization_remark : Remark<"%0">, BackendInfo,
InGroup<BackendOptimizationRemark>;
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