After
commit 3f176e1adc6bc9cc2c21222d776b51d9f43cb66b
Author: Tamar Christina <[email protected]>
Date: Thu Nov 9 13:59:39 2023 +0000
middle-end: optimize fneg (fabs (x)) to copysign (x, -1) [PR109154]
fneg (fabs (x)) is expanded to copysign (x, -1). Swap constraints for
operands[1] and operands[2] in copysign<mode>3 pattern to optimize
y = copysign (x, const_double)
instead of
y = copysign (const_double, x)
Simplify
y = copysign (x, positive_const_double)
to
y = ~signbit_mask & x
and
y = copysign (x, negative_const_double)
to
y = signbit_mask | x
gcc/
PR target/99930
PR target/122323
* config/i386/i386-expand.cc (ix86_expand_copysign): Swap
operands[1] with operands[2]. Optimize copysign (x, const_double)
instead of copysign (const_double, x).
* config/i386/i386.md (copysign<mode>3): Swap constraints for
operands[1] and operands[2].
gcc/testsuite/
PR target/99930
PR target/122323
* gcc.target/i386/builtin-copysign-2.c: New test.
* gcc.target/i386/builtin-copysign-3.c: Likewise.
* gcc.target/i386/builtin-copysign-4.c: Likewise.
* gcc.target/i386/builtin-copysign-5.c: Likewise.
* gcc.target/i386/builtin-copysign-6.c: Likewise.
* gcc.target/i386/builtin-copysign-7.c: Likewise.
* gcc.target/i386/builtin-copysign-8a.c: Likewise.
* gcc.target/i386/builtin-copysign-8b.c: Likewise.
* gcc.target/i386/builtin-fabs-1.c: Likewise.
* gcc.target/i386/builtin-fabs-2.c: Likewise.
--
H.J.
From 36f50e349da918171e6a2b5c21f3d5710db37d74 Mon Sep 17 00:00:00 2001
From: "H.J. Lu" <[email protected]>
Date: Sun, 19 Oct 2025 09:13:52 +0800
Subject: [PATCH] x86: Optimize copysign (x, const_double)
After
commit 3f176e1adc6bc9cc2c21222d776b51d9f43cb66b
Author: Tamar Christina <[email protected]>
Date: Thu Nov 9 13:59:39 2023 +0000
middle-end: optimize fneg (fabs (x)) to copysign (x, -1) [PR109154]
fneg (fabs (x)) is expanded to copysign (x, -1). Swap constraints for
operands[1] and operands[2] in copysign<mode>3 pattern to optimize
y = copysign (x, const_double)
instead of
y = copysign (const_double, x)
Simplify
y = copysign (x, positive_const_double)
to
y = ~signbit_mask & x
and
y = copysign (x, negative_const_double)
to
y = signbit_mask | x
gcc/
PR target/99930
PR target/122323
* config/i386/i386-expand.cc (ix86_expand_copysign): Swap
operands[1] with operands[2]. Optimize copysign (x, const_double)
instead of copysign (const_double, x).
* config/i386/i386.md (copysign<mode>3): Swap constraints for
operands[1] and operands[2].
gcc/testsuite/
PR target/99930
PR target/122323
* gcc.target/i386/builtin-copysign-2.c: New test.
* gcc.target/i386/builtin-copysign-3.c: Likewise.
* gcc.target/i386/builtin-copysign-4.c: Likewise.
* gcc.target/i386/builtin-copysign-5.c: Likewise.
* gcc.target/i386/builtin-copysign-6.c: Likewise.
* gcc.target/i386/builtin-copysign-7.c: Likewise.
* gcc.target/i386/builtin-copysign-8a.c: Likewise.
* gcc.target/i386/builtin-copysign-8b.c: Likewise.
* gcc.target/i386/builtin-fabs-1.c: Likewise.
* gcc.target/i386/builtin-fabs-2.c: Likewise.
Signed-off-by: H.J. Lu <[email protected]>
---
gcc/config/i386/i386-expand.cc | 46 +++++++++++--------
gcc/config/i386/i386.md | 4 +-
.../gcc.target/i386/builtin-copysign-2.c | 22 +++++++++
.../gcc.target/i386/builtin-copysign-3.c | 22 +++++++++
.../gcc.target/i386/builtin-copysign-4.c | 22 +++++++++
.../gcc.target/i386/builtin-copysign-5.c | 22 +++++++++
.../gcc.target/i386/builtin-copysign-6.c | 22 +++++++++
.../gcc.target/i386/builtin-copysign-7.c | 20 ++++++++
.../gcc.target/i386/builtin-copysign-8a.c | 21 +++++++++
.../gcc.target/i386/builtin-copysign-8b.c | 18 ++++++++
.../gcc.target/i386/builtin-fabs-1.c | 23 ++++++++++
.../gcc.target/i386/builtin-fabs-2.c | 27 +++++++++++
12 files changed, 249 insertions(+), 20 deletions(-)
create mode 100644 gcc/testsuite/gcc.target/i386/builtin-copysign-2.c
create mode 100644 gcc/testsuite/gcc.target/i386/builtin-copysign-3.c
create mode 100644 gcc/testsuite/gcc.target/i386/builtin-copysign-4.c
create mode 100644 gcc/testsuite/gcc.target/i386/builtin-copysign-5.c
create mode 100644 gcc/testsuite/gcc.target/i386/builtin-copysign-6.c
create mode 100644 gcc/testsuite/gcc.target/i386/builtin-copysign-7.c
create mode 100644 gcc/testsuite/gcc.target/i386/builtin-copysign-8a.c
create mode 100644 gcc/testsuite/gcc.target/i386/builtin-copysign-8b.c
create mode 100644 gcc/testsuite/gcc.target/i386/builtin-fabs-1.c
create mode 100644 gcc/testsuite/gcc.target/i386/builtin-fabs-2.c
diff --git a/gcc/config/i386/i386-expand.cc b/gcc/config/i386/i386-expand.cc
index 0115af4d359..5bcc35c8144 100644
--- a/gcc/config/i386/i386-expand.cc
+++ b/gcc/config/i386/i386-expand.cc
@@ -2361,34 +2361,44 @@ ix86_expand_copysign (rtx operands[])
vdest = gen_reg_rtx (vmode);
else
dest = NULL_RTX;
- op1 = lowpart_subreg (vmode, force_reg (mode, operands[2]), mode);
+ op1 = lowpart_subreg (vmode, force_reg (mode, operands[1]), mode);
mask = ix86_build_signbit_mask (vmode, TARGET_AVX512F && mode != HFmode, 0);
- if (CONST_DOUBLE_P (operands[1]))
+ if (CONST_DOUBLE_P (operands[2]))
{
- op0 = simplify_unary_operation (ABS, mode, operands[1], mode);
- /* Optimize for 0, simplify b = copy_signf (0.0f, a) to b = mask & a. */
- if (op0 == CONST0_RTX (mode))
+ if (real_isneg (CONST_DOUBLE_REAL_VALUE (operands[2])))
+ /* Simplify b = copysign (a, negative) to b = mask | a. */
+ op1 = gen_rtx_IOR (vmode, mask, op1);
+ else
{
- emit_move_insn (vdest, gen_rtx_AND (vmode, mask, op1));
- if (dest)
- emit_move_insn (dest, lowpart_subreg (mode, vdest, vmode));
- return;
+ /* Simplify b = copysign (a, positive) to b = invert_mask & a. */
+ rtx invert_mask
+ = ix86_build_signbit_mask (vmode,
+ TARGET_AVX512F && mode != HFmode,
+ true);
+ op1 = gen_rtx_AND (vmode, invert_mask, op1);
}
-
- if (GET_MODE_SIZE (mode) < 16)
- op0 = ix86_build_const_vector (vmode, false, op0);
- op0 = force_reg (vmode, op0);
+ emit_move_insn (vdest, op1);
+ if (dest)
+ emit_move_insn (dest, lowpart_subreg (mode, vdest, vmode));
+ return;
}
else
- op0 = lowpart_subreg (vmode, force_reg (mode, operands[1]), mode);
+ op0 = lowpart_subreg (vmode, force_reg (mode, operands[2]), mode);
op2 = gen_reg_rtx (vmode);
op3 = gen_reg_rtx (vmode);
- emit_move_insn (op2, gen_rtx_AND (vmode,
- gen_rtx_NOT (vmode, mask),
- op0));
- emit_move_insn (op3, gen_rtx_AND (vmode, mask, op1));
+ rtx invert_mask;
+ /* NB: Generate vmovdqa, vpandn, vpand, vpor for AVX and generate pand,
+ pand, por for SSE. */
+ if (TARGET_AVX)
+ invert_mask = gen_rtx_NOT (vmode, mask);
+ else
+ invert_mask = ix86_build_signbit_mask (vmode,
+ TARGET_AVX512F && mode != HFmode,
+ true);
+ emit_move_insn (op2, gen_rtx_AND (vmode, invert_mask, op1));
+ emit_move_insn (op3, gen_rtx_AND (vmode, mask, op0));
emit_move_insn (vdest, gen_rtx_IOR (vmode, op2, op3));
if (dest)
emit_move_insn (dest, lowpart_subreg (mode, vdest, vmode));
diff --git a/gcc/config/i386/i386.md b/gcc/config/i386/i386.md
index cea6c152f2b..8a3e336bee6 100644
--- a/gcc/config/i386/i386.md
+++ b/gcc/config/i386/i386.md
@@ -15084,8 +15084,8 @@ (define_insn "*<code><mode>2_i387"
(define_expand "copysign<mode>3"
[(match_operand:SSEMODEF 0 "register_operand")
- (match_operand:SSEMODEF 1 "nonmemory_operand")
- (match_operand:SSEMODEF 2 "register_operand")]
+ (match_operand:SSEMODEF 1 "register_operand")
+ (match_operand:SSEMODEF 2 "nonmemory_operand")]
"(SSE_FLOAT_MODE_P (<MODE>mode) && TARGET_SSE_MATH)
|| (TARGET_SSE && (<MODE>mode == TFmode))
|| (TARGET_AVX512FP16 && (<MODE>mode ==HFmode))"
diff --git a/gcc/testsuite/gcc.target/i386/builtin-copysign-2.c b/gcc/testsuite/gcc.target/i386/builtin-copysign-2.c
new file mode 100644
index 00000000000..d90c5a49a3a
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/builtin-copysign-2.c
@@ -0,0 +1,22 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -mno-avx -msse2" } */
+/* Keep labels and directives ('.cfi_startproc', '.cfi_endproc'). */
+/* { dg-final { check-function-bodies "**" "" "" { target { ! ia32 } } {^\t?\.} } } */
+
+/*
+**foo:
+**.LFB[0-9]+:
+** .cfi_startproc
+** andps .LC[0-9]+\(%rip\), %xmm0
+** ret
+**...
+*/
+
+float
+foo (float x)
+{
+ return __builtin_copysignf (x, 0.0);
+}
+
+/* { dg-final { scan-assembler-times ".long 0" 3 { target { ! ia32 } } } } */
+/* { dg-final { scan-assembler-times ".long 2147483647" 1 { target { ! ia32 } } } } */
diff --git a/gcc/testsuite/gcc.target/i386/builtin-copysign-3.c b/gcc/testsuite/gcc.target/i386/builtin-copysign-3.c
new file mode 100644
index 00000000000..d3b4dd5a4af
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/builtin-copysign-3.c
@@ -0,0 +1,22 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -mno-avx -msse2" } */
+/* Keep labels and directives ('.cfi_startproc', '.cfi_endproc'). */
+/* { dg-final { check-function-bodies "**" "" "" { target { ! ia32 } } {^\t?\.} } } */
+
+/*
+**foo:
+**.LFB[0-9]+:
+** .cfi_startproc
+** orps .LC[0-9]+\(%rip\), %xmm0
+** ret
+**...
+*/
+
+float
+foo (float x)
+{
+ return __builtin_copysignf (x, -3.0);
+}
+
+/* { dg-final { scan-assembler-times ".long 0" 3 { target { ! ia32 } } } } */
+/* { dg-final { scan-assembler-times ".long -2147483648" 1 { target { ! ia32 } } } } */
diff --git a/gcc/testsuite/gcc.target/i386/builtin-copysign-4.c b/gcc/testsuite/gcc.target/i386/builtin-copysign-4.c
new file mode 100644
index 00000000000..9886fdcc9ae
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/builtin-copysign-4.c
@@ -0,0 +1,22 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -mno-avx -msse2" } */
+/* Keep labels and directives ('.cfi_startproc', '.cfi_endproc'). */
+/* { dg-final { check-function-bodies "**" "" "" { target { ! ia32 } } {^\t?\.} } } */
+
+/*
+**foo:
+**.LFB[0-9]+:
+** .cfi_startproc
+** pand .LC[0-9]+\(%rip\), %xmm0
+** ret
+**...
+*/
+
+__float128
+foo (__float128 x)
+{
+ return __builtin_copysignq (x, 0.0);
+}
+
+/* { dg-final { scan-assembler-times ".long -1" 3 { target { ! ia32 } } } } */
+/* { dg-final { scan-assembler-times ".long 2147483647" 1 { target { ! ia32 } } } } */
diff --git a/gcc/testsuite/gcc.target/i386/builtin-copysign-5.c b/gcc/testsuite/gcc.target/i386/builtin-copysign-5.c
new file mode 100644
index 00000000000..3f4df5f779b
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/builtin-copysign-5.c
@@ -0,0 +1,22 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -mno-avx -msse2" } */
+/* Keep labels and directives ('.cfi_startproc', '.cfi_endproc'). */
+/* { dg-final { check-function-bodies "**" "" "" { target { ! ia32 } } {^\t?\.} } } */
+
+/*
+**foo:
+**.LFB[0-9]+:
+** .cfi_startproc
+** pand .LC[0-9]+\(%rip\), %xmm0
+** ret
+**...
+*/
+
+__float128
+foo (__float128 x)
+{
+ return __builtin_copysignq (0.0, x);
+}
+
+/* { dg-final { scan-assembler-times ".long 0" 3 { target { ! ia32 } } } } */
+/* { dg-final { scan-assembler-times ".long -2147483648" 1 { target { ! ia32 } } } } */
diff --git a/gcc/testsuite/gcc.target/i386/builtin-copysign-6.c b/gcc/testsuite/gcc.target/i386/builtin-copysign-6.c
new file mode 100644
index 00000000000..5b6eb517f82
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/builtin-copysign-6.c
@@ -0,0 +1,22 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -mno-avx -msse2" } */
+/* Keep labels and directives ('.cfi_startproc', '.cfi_endproc'). */
+/* { dg-final { check-function-bodies "**" "" "" { target { ! ia32 } } {^\t?\.} } } */
+
+/*
+**foo:
+**.LFB[0-9]+:
+** .cfi_startproc
+** pand .LC[0-9]+\(%rip\), %xmm0
+** ret
+**...
+*/
+
+__float128
+foo (__float128 x)
+{
+ return __builtin_copysignq (x, 3.4);
+}
+
+/* { dg-final { scan-assembler-times ".long -1" 3 { target { ! ia32 } } } } */
+/* { dg-final { scan-assembler-times ".long 2147483647" 1 { target { ! ia32 } } } } */
diff --git a/gcc/testsuite/gcc.target/i386/builtin-copysign-7.c b/gcc/testsuite/gcc.target/i386/builtin-copysign-7.c
new file mode 100644
index 00000000000..012fb14a85e
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/builtin-copysign-7.c
@@ -0,0 +1,20 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -mno-avx -msse2" } */
+/* Keep labels and directives ('.cfi_startproc', '.cfi_endproc'). */
+/* { dg-final { check-function-bodies "**" "" "" { target { ! ia32 } } {^\t?\.} } } */
+
+/*
+**foo:
+**.LFB[0-9]+:
+** .cfi_startproc
+** pand .LC[0-9]+\(%rip\), %xmm0
+** por .LC[0-9]+\(%rip\), %xmm0
+** ret
+**...
+*/
+
+__float128
+foo (__float128 x)
+{
+ return __builtin_copysignq (3.4, x);
+}
diff --git a/gcc/testsuite/gcc.target/i386/builtin-copysign-8a.c b/gcc/testsuite/gcc.target/i386/builtin-copysign-8a.c
new file mode 100644
index 00000000000..e390ee27aa3
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/builtin-copysign-8a.c
@@ -0,0 +1,21 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -mno-avx -msse2" } */
+/* Keep labels and directives ('.cfi_startproc', '.cfi_endproc'). */
+/* { dg-final { check-function-bodies "**" "" "" { target { ! ia32 } } {^\t?\.} } } */
+
+/*
+**foo:
+**.LFB[0-9]+:
+** .cfi_startproc
+** pand .LC[0-9]+\(%rip\), %xmm0
+** pand .LC[0-9]+\(%rip\), %xmm1
+** por %xmm1, %xmm0
+** ret
+**...
+*/
+
+__float128
+foo (__float128 x, __float128 y)
+{
+ return __builtin_copysignq (x, y);
+}
diff --git a/gcc/testsuite/gcc.target/i386/builtin-copysign-8b.c b/gcc/testsuite/gcc.target/i386/builtin-copysign-8b.c
new file mode 100644
index 00000000000..8f0cb27a246
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/builtin-copysign-8b.c
@@ -0,0 +1,18 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -mno-avx512f -mavx" } */
+/* Keep labels and directives ('.cfi_startproc', '.cfi_endproc'). */
+/* { dg-final { check-function-bodies "**" "" "" { target { ! ia32 } } {^\t?\.} } } */
+
+/*
+**foo:
+**.LFB[0-9]+:
+** .cfi_startproc
+** vmovdqa .LC[0-9]+\(%rip\), %xmm2
+** vpandn %xmm0, %xmm2, %xmm0
+** vpand %xmm2, %xmm1, %xmm1
+** vpor %xmm1, %xmm0, %xmm0
+** ret
+**...
+*/
+
+#include "builtin-copysign-8a.c"
diff --git a/gcc/testsuite/gcc.target/i386/builtin-fabs-1.c b/gcc/testsuite/gcc.target/i386/builtin-fabs-1.c
new file mode 100644
index 00000000000..a9a25f6bd4b
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/builtin-fabs-1.c
@@ -0,0 +1,23 @@
+/* PR target/122323 */
+/* { dg-do compile } */
+/* { dg-options "-O2 -mno-avx -msse2" } */
+/* Keep labels and directives ('.cfi_startproc', '.cfi_endproc'). */
+/* { dg-final { check-function-bodies "**" "" "" { target { ! ia32 } } {^\t?\.} } } */
+
+/*
+**foo:
+**.LFB[0-9]+:
+** .cfi_startproc
+** orps .LC[0-9]+\(%rip\), %xmm0
+** ret
+**...
+*/
+
+float
+foo (float x)
+{
+ return -__builtin_fabsf (x);
+}
+
+/* { dg-final { scan-assembler-times ".long 0" 3 { target { ! ia32 } } } } */
+/* { dg-final { scan-assembler-times ".long -2147483648" 1 { target { ! ia32 } } } } */
diff --git a/gcc/testsuite/gcc.target/i386/builtin-fabs-2.c b/gcc/testsuite/gcc.target/i386/builtin-fabs-2.c
new file mode 100644
index 00000000000..093fd2ef8b9
--- /dev/null
+++ b/gcc/testsuite/gcc.target/i386/builtin-fabs-2.c
@@ -0,0 +1,27 @@
+/* PR target/99930 */
+/* { dg-do compile } */
+/* { dg-options "-O2 -mno-avx -msse2" } */
+/* Keep labels and directives ('.cfi_startproc', '.cfi_endproc'). */
+/* { dg-final { check-function-bodies "**" "" "" { target { ! ia32 } } {^\t?\.} } } */
+
+/*
+**foo:
+**...
+** ja .L[0-9]+
+** movss 4\(%rdi\), %xmm1
+** orps %xmm1, %xmm0
+** comiss %xmm0, %xmm2
+** seta %al
+** ret
+**...
+*/
+
+
+bool
+foo (float n[2], float m)
+{
+ for (int i = 0; i < 2; i++)
+ if (m > -__builtin_fabsf (n[i]))
+ return true;
+ return false;
+}
--
2.51.0
