When passing 0xff as an unsigned char function argument with the C frontend
promotion, expand_normal used to get
<integer_cst 0x7fffe6aa23a8 type <integer_type 0x7fffe98225e8 int> constant 255>
and returned the rtx value using the sign-extended representation:
(const_int 255 [0xff])
But after
commit a670ebde3995481225ec62b29686ec07a21e5c10
Author: H.J. Lu <hjl.to...@gmail.com>
Date: Thu Nov 21 07:54:35 2024 +0800
Drop targetm.promote_prototypes from C, C++ and Ada frontends
expand_normal now gets
<integer_cst 0x7fffe9824018 type <integer_type 0x7fffe9822348 unsigned char > co
nstant 255>
and returns
(const_int -1 [0xffffffffffffffff])
which doesn't work with the predicates nor the instruction templates which
expect the unsigned expanded value. Extract the unsigned char and short
integer constants to return
(const_int 255 [0xff])
so that the expanded value is always unsigned, without the C frontend
promotion.
PR target/117547
* config/i386/i386-expand.cc (ix86_expand_unsigned_small_int_cst_argumen
t):
New function.
(ix86_expand_args_builtin): Call
ix86_expand_unsigned_small_int_cst_argument to expand the argument
before calling fixup_modeless_constant.
(ix86_expand_round_builtin): Likewise.
(ix86_expand_special_args_builtin): Likewise.
(ix86_expand_builtin): Likewise.
--
H.J.
From a7d29729de7451f5ef47d85480905fec0670bd7c Mon Sep 17 00:00:00 2001
From: "H.J. Lu" <hjl.to...@gmail.com>
Date: Tue, 12 Nov 2024 09:03:31 +0800
Subject: [PATCH] i386: Add ix86_expand_unsigned_small_int_cst_argument
When passing 0xff as an unsigned char function argument with the C frontend
promotion, expand_normal used to get
<integer_cst 0x7fffe6aa23a8 type <integer_type 0x7fffe98225e8 int> constant 255>
and returned the rtx value using the sign-extended representation:
(const_int 255 [0xff])
But after
commit a670ebde3995481225ec62b29686ec07a21e5c10
Author: H.J. Lu <hjl.to...@gmail.com>
Date: Thu Nov 21 07:54:35 2024 +0800
Drop targetm.promote_prototypes from C, C++ and Ada frontends
expand_normal now gets
<integer_cst 0x7fffe9824018 type <integer_type 0x7fffe9822348 unsigned char > constant 255>
and returns
(const_int -1 [0xffffffffffffffff])
which doesn't work with the predicates nor the instruction templates which
expect the unsigned expanded value. Extract the unsigned char and short
integer constants to return
(const_int 255 [0xff])
so that the expanded value is always unsigned, without the C frontend
promotion.
PR target/117547
* config/i386/i386-expand.cc (ix86_expand_unsigned_small_int_cst_argument):
New function.
(ix86_expand_args_builtin): Call
ix86_expand_unsigned_small_int_cst_argument to expand the argument
before calling fixup_modeless_constant.
(ix86_expand_round_builtin): Likewise.
(ix86_expand_special_args_builtin): Likewise.
(ix86_expand_builtin): Likewise.
Signed-off-by: H.J. Lu <hjl.to...@gmail.com>
---
gcc/config/i386/i386-expand.cc | 58 +++++++++++++++++++++++++++++++---
1 file changed, 53 insertions(+), 5 deletions(-)
diff --git a/gcc/config/i386/i386-expand.cc b/gcc/config/i386/i386-expand.cc
index a3148008089..388e65192e4 100644
--- a/gcc/config/i386/i386-expand.cc
+++ b/gcc/config/i386/i386-expand.cc
@@ -11250,6 +11250,54 @@ fixup_modeless_constant (rtx x, machine_mode mode)
return x;
}
+/* Expand the outgoing argument ARG to extract unsigned char and short
+ integer constants suitable for the predicates and the instruction
+ templates which expect the unsigned expanded value. */
+
+static rtx
+ix86_expand_unsigned_small_int_cst_argument (tree arg)
+{
+ /* When passing 0xff as an unsigned char function argument with the
+ C frontend promotion, expand_normal gets
+
+ <integer_cst 0x7fffe6aa23a8 type <integer_type 0x7fffe98225e8 int> constant 255>
+
+ and returns the rtx value using the sign-extended representation:
+
+ (const_int 255 [0xff])
+
+ Without the C frontend promotion, expand_normal gets
+
+ <integer_cst 0x7fffe9824018 type <integer_type 0x7fffe9822348 unsigned char > constant 255>
+
+ and returns
+
+ (const_int -1 [0xffffffffffffffff])
+
+ which doesn't work with the predicates nor the instruction templates
+ which expect the unsigned expanded value. Extract the unsigned char
+ and short integer constants to return
+
+ (const_int 255 [0xff])
+
+ so that the expanded value is always unsigned, without the C frontend
+ promotion. */
+
+ if (TREE_CODE (arg) == INTEGER_CST)
+ {
+ tree type = TREE_TYPE (arg);
+ if (INTEGRAL_TYPE_P (type)
+ && TYPE_UNSIGNED (type)
+ && TYPE_PRECISION (type) < TYPE_PRECISION (integer_type_node))
+ {
+ HOST_WIDE_INT cst = TREE_INT_CST_LOW (arg);
+ return GEN_INT (cst);
+ }
+ }
+
+ return expand_normal (arg);
+}
+
/* Subroutine of ix86_expand_builtin to take care of insns with
variable number of operands. */
@@ -12148,7 +12196,7 @@ ix86_expand_args_builtin (const struct builtin_description *d,
for (i = 0; i < nargs; i++)
{
tree arg = CALL_EXPR_ARG (exp, i);
- rtx op = expand_normal (arg);
+ rtx op = ix86_expand_unsigned_small_int_cst_argument (arg);
machine_mode mode = insn_p->operand[i + 1].mode;
/* Need to fixup modeless constant before testing predicate. */
op = fixup_modeless_constant (op, mode);
@@ -12843,7 +12891,7 @@ ix86_expand_round_builtin (const struct builtin_description *d,
for (i = 0; i < nargs; i++)
{
tree arg = CALL_EXPR_ARG (exp, i);
- rtx op = expand_normal (arg);
+ rtx op = ix86_expand_unsigned_small_int_cst_argument (arg);
machine_mode mode = insn_p->operand[i + 1].mode;
bool match = insn_p->operand[i + 1].predicate (op, mode);
@@ -13328,7 +13376,7 @@ ix86_expand_special_args_builtin (const struct builtin_description *d,
machine_mode mode = insn_p->operand[i + 1].mode;
arg = CALL_EXPR_ARG (exp, i + arg_adjust);
- op = expand_normal (arg);
+ op = ix86_expand_unsigned_small_int_cst_argument (arg);
if (i == memory)
{
@@ -15472,7 +15520,7 @@ rdseed_step:
op0 = expand_normal (arg0);
op1 = expand_normal (arg1);
op2 = expand_normal (arg2);
- op3 = expand_normal (arg3);
+ op3 = ix86_expand_unsigned_small_int_cst_argument (arg3);
op4 = expand_normal (arg4);
/* Note the arg order is different from the operand order. */
mode0 = insn_data[icode].operand[1].mode;
@@ -15687,7 +15735,7 @@ rdseed_step:
arg3 = CALL_EXPR_ARG (exp, 3);
arg4 = CALL_EXPR_ARG (exp, 4);
op0 = expand_normal (arg0);
- op1 = expand_normal (arg1);
+ op1 = ix86_expand_unsigned_small_int_cst_argument (arg1);
op2 = expand_normal (arg2);
op3 = expand_normal (arg3);
op4 = expand_normal (arg4);
--
2.49.0
