[llvm-branch-commits] [llvm] [DAGCombiner] Relax nsz constraint with fp->int->fp optimizations (PR #164503)
Guy David via llvm-branch-commits
llvm-branch-commits at lists.llvm.org
Tue Dec 9 04:32:32 PST 2025
https://github.com/guy-david updated https://github.com/llvm/llvm-project/pull/164503
>From 9a971cc4b5dbf487c816fec336155f00fd92eee1 Mon Sep 17 00:00:00 2001
From: Guy David <guyda at apple.com>
Date: Tue, 9 Dec 2025 14:27:34 +0200
Subject: [PATCH] [DAGCombiner] Relax nsz constraint with fp->int->fp
optimizations
---
llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp | 3 +-
llvm/test/CodeGen/AArch64/fp-to-int-to-fp.ll | 21 +++
llvm/test/CodeGen/X86/setoeq.ll | 142 +++---------------
3 files changed, 41 insertions(+), 125 deletions(-)
diff --git a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
index ad75d2cf5a8ac..1a5db5cbaa457 100644
--- a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
@@ -19058,7 +19058,8 @@ static SDValue foldFPToIntToFP(SDNode *N, const SDLoc &DL, SelectionDAG &DAG,
bool IsSigned = N->getOpcode() == ISD::SINT_TO_FP;
assert(IsSigned || IsUnsigned);
- bool IsSignedZeroSafe = DAG.getTarget().Options.NoSignedZerosFPMath;
+ bool IsSignedZeroSafe = DAG.getTarget().Options.NoSignedZerosFPMath ||
+ DAG.canIgnoreSignBitOfZero(SDValue(N, 0));
// For signed conversions: The optimization changes signed zero behavior.
if (IsSigned && !IsSignedZeroSafe)
return SDValue();
diff --git a/llvm/test/CodeGen/AArch64/fp-to-int-to-fp.ll b/llvm/test/CodeGen/AArch64/fp-to-int-to-fp.ll
index 9a8c555953611..8aa3df8546b31 100644
--- a/llvm/test/CodeGen/AArch64/fp-to-int-to-fp.ll
+++ b/llvm/test/CodeGen/AArch64/fp-to-int-to-fp.ll
@@ -42,6 +42,27 @@ entry:
ret float %f
}
+define i1 @test_implicit_nsz(float %x) {
+; CHECK-LABEL: test_implicit_nsz:
+; CHECK: // %bb.0: // %entry
+; CHECK-NEXT: frintz s0, s0
+; CHECK-NEXT: fcmp s0, #0.0
+; CHECK-NEXT: cset w0, eq
+; CHECK-NEXT: ret
+;
+; NO-SIGNED-ZEROS-LABEL: test_implicit_nsz:
+; NO-SIGNED-ZEROS: // %bb.0: // %entry
+; NO-SIGNED-ZEROS-NEXT: frintz s0, s0
+; NO-SIGNED-ZEROS-NEXT: fcmp s0, #0.0
+; NO-SIGNED-ZEROS-NEXT: cset w0, eq
+; NO-SIGNED-ZEROS-NEXT: ret
+entry:
+ %i = fptoui float %x to i32
+ %f = uitofp i32 %i to float
+ %cmp = fcmp oeq float %f, 0.0
+ ret i1 %cmp
+}
+
define float @test_signed_min_max(float %x) {
; CHECK-LABEL: test_signed_min_max:
; CHECK: // %bb.0: // %entry
diff --git a/llvm/test/CodeGen/X86/setoeq.ll b/llvm/test/CodeGen/X86/setoeq.ll
index 131e279aa645c..8aebf8eaa62e7 100644
--- a/llvm/test/CodeGen/X86/setoeq.ll
+++ b/llvm/test/CodeGen/X86/setoeq.ll
@@ -18,8 +18,7 @@ define zeroext i8 @oeq_f64_i32(double %x) nounwind readnone {
; AVX-LABEL: oeq_f64_i32:
; AVX: # %bb.0: # %entry
; AVX-NEXT: vmovsd {{.*#+}} xmm0 = mem[0],zero
-; AVX-NEXT: vcvttpd2dq %xmm0, %xmm1
-; AVX-NEXT: vcvtdq2pd %xmm1, %xmm1
+; AVX-NEXT: vroundsd $11, %xmm0, %xmm0, %xmm1
; AVX-NEXT: vcmpeqsd %xmm0, %xmm1, %xmm0
; AVX-NEXT: vmovd %xmm0, %eax
; AVX-NEXT: andl $1, %eax
@@ -29,8 +28,7 @@ define zeroext i8 @oeq_f64_i32(double %x) nounwind readnone {
; AVX512-LABEL: oeq_f64_i32:
; AVX512: # %bb.0: # %entry
; AVX512-NEXT: vmovsd {{.*#+}} xmm0 = mem[0],zero
-; AVX512-NEXT: vcvttpd2dq %xmm0, %xmm1
-; AVX512-NEXT: vcvtdq2pd %xmm1, %xmm1
+; AVX512-NEXT: vroundsd $11, %xmm0, %xmm0, %xmm1
; AVX512-NEXT: vcmpeqsd %xmm0, %xmm1, %k0
; AVX512-NEXT: kmovd %k0, %eax
; AVX512-NEXT: # kill: def $al killed $al killed $eax
@@ -67,16 +65,7 @@ define zeroext i8 @oeq_f64_u32(double %x) nounwind readnone {
; AVX-LABEL: oeq_f64_u32:
; AVX: # %bb.0: # %entry
; AVX-NEXT: vmovsd {{.*#+}} xmm0 = mem[0],zero
-; AVX-NEXT: vcvttsd2si %xmm0, %eax
-; AVX-NEXT: movl %eax, %ecx
-; AVX-NEXT: sarl $31, %ecx
-; AVX-NEXT: vsubsd {{\.?LCPI[0-9]+_[0-9]+}}, %xmm0, %xmm1
-; AVX-NEXT: vcvttsd2si %xmm1, %edx
-; AVX-NEXT: andl %ecx, %edx
-; AVX-NEXT: orl %eax, %edx
-; AVX-NEXT: vmovd %edx, %xmm1
-; AVX-NEXT: vpor {{\.?LCPI[0-9]+_[0-9]+}}, %xmm1, %xmm1
-; AVX-NEXT: vsubsd {{\.?LCPI[0-9]+_[0-9]+}}, %xmm1, %xmm1
+; AVX-NEXT: vroundsd $11, %xmm0, %xmm0, %xmm1
; AVX-NEXT: vcmpeqsd %xmm0, %xmm1, %xmm0
; AVX-NEXT: vmovd %xmm0, %eax
; AVX-NEXT: andl $1, %eax
@@ -86,8 +75,7 @@ define zeroext i8 @oeq_f64_u32(double %x) nounwind readnone {
; AVX512-LABEL: oeq_f64_u32:
; AVX512: # %bb.0: # %entry
; AVX512-NEXT: vmovsd {{.*#+}} xmm0 = mem[0],zero
-; AVX512-NEXT: vcvttsd2usi %xmm0, %eax
-; AVX512-NEXT: vcvtusi2sd %eax, %xmm7, %xmm1
+; AVX512-NEXT: vroundsd $11, %xmm0, %xmm0, %xmm1
; AVX512-NEXT: vcmpeqsd %xmm0, %xmm1, %k0
; AVX512-NEXT: kmovd %k0, %eax
; AVX512-NEXT: # kill: def $al killed $al killed $eax
@@ -131,35 +119,21 @@ define zeroext i8 @oeq_f64_i64(double %x) nounwind readnone {
;
; AVX-LABEL: oeq_f64_i64:
; AVX: # %bb.0: # %entry
-; AVX-NEXT: pushl %ebp
-; AVX-NEXT: movl %esp, %ebp
-; AVX-NEXT: andl $-8, %esp
-; AVX-NEXT: subl $24, %esp
; AVX-NEXT: vmovsd {{.*#+}} xmm0 = mem[0],zero
-; AVX-NEXT: vmovsd %xmm0, (%esp)
-; AVX-NEXT: fldl (%esp)
-; AVX-NEXT: fisttpll (%esp)
-; AVX-NEXT: vmovsd {{.*#+}} xmm1 = mem[0],zero
-; AVX-NEXT: vmovlps %xmm1, {{[0-9]+}}(%esp)
-; AVX-NEXT: fildll {{[0-9]+}}(%esp)
-; AVX-NEXT: fstpl {{[0-9]+}}(%esp)
-; AVX-NEXT: vcmpeqsd {{[0-9]+}}(%esp), %xmm0, %xmm0
+; AVX-NEXT: vroundsd $11, %xmm0, %xmm0, %xmm1
+; AVX-NEXT: vcmpeqsd %xmm0, %xmm1, %xmm0
; AVX-NEXT: vmovd %xmm0, %eax
; AVX-NEXT: andl $1, %eax
; AVX-NEXT: # kill: def $al killed $al killed $eax
-; AVX-NEXT: movl %ebp, %esp
-; AVX-NEXT: popl %ebp
; AVX-NEXT: retl
;
; AVX512-LABEL: oeq_f64_i64:
; AVX512: # %bb.0: # %entry
; AVX512-NEXT: vmovsd {{.*#+}} xmm0 = mem[0],zero
-; AVX512-NEXT: vcvttpd2qq %xmm0, %xmm1
-; AVX512-NEXT: vcvtqq2pd %ymm1, %ymm1
+; AVX512-NEXT: vroundsd $11, %xmm0, %xmm0, %xmm1
; AVX512-NEXT: vcmpeqsd %xmm0, %xmm1, %k0
; AVX512-NEXT: kmovd %k0, %eax
; AVX512-NEXT: # kill: def $al killed $al killed $eax
-; AVX512-NEXT: vzeroupper
; AVX512-NEXT: retl
entry:
%0 = fptosi double %x to i64
@@ -216,48 +190,21 @@ define zeroext i8 @oeq_f64_u64(double %x) nounwind readnone {
;
; AVX-LABEL: oeq_f64_u64:
; AVX: # %bb.0: # %entry
-; AVX-NEXT: pushl %ebp
-; AVX-NEXT: movl %esp, %ebp
-; AVX-NEXT: andl $-8, %esp
-; AVX-NEXT: subl $8, %esp
; AVX-NEXT: vmovsd {{.*#+}} xmm0 = mem[0],zero
-; AVX-NEXT: vmovsd {{.*#+}} xmm1 = [9.2233720368547758E+18,0.0E+0]
-; AVX-NEXT: vucomisd %xmm0, %xmm1
-; AVX-NEXT: jbe .LBB3_2
-; AVX-NEXT: # %bb.1: # %entry
-; AVX-NEXT: vxorpd %xmm1, %xmm1, %xmm1
-; AVX-NEXT: .LBB3_2: # %entry
-; AVX-NEXT: vsubsd %xmm1, %xmm0, %xmm1
-; AVX-NEXT: vmovsd %xmm1, (%esp)
-; AVX-NEXT: fldl (%esp)
-; AVX-NEXT: fisttpll (%esp)
-; AVX-NEXT: setbe %al
-; AVX-NEXT: movzbl %al, %eax
-; AVX-NEXT: shll $31, %eax
-; AVX-NEXT: xorl {{[0-9]+}}(%esp), %eax
-; AVX-NEXT: vmovd {{.*#+}} xmm1 = mem[0],zero,zero,zero
-; AVX-NEXT: vpinsrd $1, %eax, %xmm1, %xmm1
-; AVX-NEXT: vpunpckldq {{.*#+}} xmm1 = xmm1[0],mem[0],xmm1[1],mem[1]
-; AVX-NEXT: vsubpd {{\.?LCPI[0-9]+_[0-9]+}}, %xmm1, %xmm1
-; AVX-NEXT: vshufpd {{.*#+}} xmm2 = xmm1[1,0]
-; AVX-NEXT: vaddsd %xmm1, %xmm2, %xmm1
+; AVX-NEXT: vroundsd $11, %xmm0, %xmm0, %xmm1
; AVX-NEXT: vcmpeqsd %xmm0, %xmm1, %xmm0
; AVX-NEXT: vmovd %xmm0, %eax
; AVX-NEXT: andl $1, %eax
; AVX-NEXT: # kill: def $al killed $al killed $eax
-; AVX-NEXT: movl %ebp, %esp
-; AVX-NEXT: popl %ebp
; AVX-NEXT: retl
;
; AVX512-LABEL: oeq_f64_u64:
; AVX512: # %bb.0: # %entry
; AVX512-NEXT: vmovsd {{.*#+}} xmm0 = mem[0],zero
-; AVX512-NEXT: vcvttpd2uqq %xmm0, %xmm1
-; AVX512-NEXT: vcvtuqq2pd %ymm1, %ymm1
+; AVX512-NEXT: vroundsd $11, %xmm0, %xmm0, %xmm1
; AVX512-NEXT: vcmpeqsd %xmm0, %xmm1, %k0
; AVX512-NEXT: kmovd %k0, %eax
; AVX512-NEXT: # kill: def $al killed $al killed $eax
-; AVX512-NEXT: vzeroupper
; AVX512-NEXT: retl
entry:
%0 = fptoui double %x to i64
@@ -282,8 +229,7 @@ define zeroext i8 @une_f64_i32(double %x) nounwind readnone {
; AVX-LABEL: une_f64_i32:
; AVX: # %bb.0: # %entry
; AVX-NEXT: vmovsd {{.*#+}} xmm0 = mem[0],zero
-; AVX-NEXT: vcvttpd2dq %xmm0, %xmm1
-; AVX-NEXT: vcvtdq2pd %xmm1, %xmm1
+; AVX-NEXT: vroundsd $11, %xmm0, %xmm0, %xmm1
; AVX-NEXT: vcmpneqsd %xmm0, %xmm1, %xmm0
; AVX-NEXT: vmovd %xmm0, %eax
; AVX-NEXT: andl $1, %eax
@@ -293,8 +239,7 @@ define zeroext i8 @une_f64_i32(double %x) nounwind readnone {
; AVX512-LABEL: une_f64_i32:
; AVX512: # %bb.0: # %entry
; AVX512-NEXT: vmovsd {{.*#+}} xmm0 = mem[0],zero
-; AVX512-NEXT: vcvttpd2dq %xmm0, %xmm1
-; AVX512-NEXT: vcvtdq2pd %xmm1, %xmm1
+; AVX512-NEXT: vroundsd $11, %xmm0, %xmm0, %xmm1
; AVX512-NEXT: vcmpneqsd %xmm0, %xmm1, %k0
; AVX512-NEXT: kmovd %k0, %eax
; AVX512-NEXT: # kill: def $al killed $al killed $eax
@@ -331,16 +276,7 @@ define zeroext i8 @une_f64_u32(double %x) nounwind readnone {
; AVX-LABEL: une_f64_u32:
; AVX: # %bb.0: # %entry
; AVX-NEXT: vmovsd {{.*#+}} xmm0 = mem[0],zero
-; AVX-NEXT: vcvttsd2si %xmm0, %eax
-; AVX-NEXT: movl %eax, %ecx
-; AVX-NEXT: sarl $31, %ecx
-; AVX-NEXT: vsubsd {{\.?LCPI[0-9]+_[0-9]+}}, %xmm0, %xmm1
-; AVX-NEXT: vcvttsd2si %xmm1, %edx
-; AVX-NEXT: andl %ecx, %edx
-; AVX-NEXT: orl %eax, %edx
-; AVX-NEXT: vmovd %edx, %xmm1
-; AVX-NEXT: vpor {{\.?LCPI[0-9]+_[0-9]+}}, %xmm1, %xmm1
-; AVX-NEXT: vsubsd {{\.?LCPI[0-9]+_[0-9]+}}, %xmm1, %xmm1
+; AVX-NEXT: vroundsd $11, %xmm0, %xmm0, %xmm1
; AVX-NEXT: vcmpneqsd %xmm0, %xmm1, %xmm0
; AVX-NEXT: vmovd %xmm0, %eax
; AVX-NEXT: andl $1, %eax
@@ -350,8 +286,7 @@ define zeroext i8 @une_f64_u32(double %x) nounwind readnone {
; AVX512-LABEL: une_f64_u32:
; AVX512: # %bb.0: # %entry
; AVX512-NEXT: vmovsd {{.*#+}} xmm0 = mem[0],zero
-; AVX512-NEXT: vcvttsd2usi %xmm0, %eax
-; AVX512-NEXT: vcvtusi2sd %eax, %xmm7, %xmm1
+; AVX512-NEXT: vroundsd $11, %xmm0, %xmm0, %xmm1
; AVX512-NEXT: vcmpneqsd %xmm0, %xmm1, %k0
; AVX512-NEXT: kmovd %k0, %eax
; AVX512-NEXT: # kill: def $al killed $al killed $eax
@@ -395,35 +330,21 @@ define zeroext i8 @une_f64_i64(double %x) nounwind readnone {
;
; AVX-LABEL: une_f64_i64:
; AVX: # %bb.0: # %entry
-; AVX-NEXT: pushl %ebp
-; AVX-NEXT: movl %esp, %ebp
-; AVX-NEXT: andl $-8, %esp
-; AVX-NEXT: subl $24, %esp
; AVX-NEXT: vmovsd {{.*#+}} xmm0 = mem[0],zero
-; AVX-NEXT: vmovsd %xmm0, (%esp)
-; AVX-NEXT: fldl (%esp)
-; AVX-NEXT: fisttpll (%esp)
-; AVX-NEXT: vmovsd {{.*#+}} xmm1 = mem[0],zero
-; AVX-NEXT: vmovlps %xmm1, {{[0-9]+}}(%esp)
-; AVX-NEXT: fildll {{[0-9]+}}(%esp)
-; AVX-NEXT: fstpl {{[0-9]+}}(%esp)
-; AVX-NEXT: vcmpneqsd {{[0-9]+}}(%esp), %xmm0, %xmm0
+; AVX-NEXT: vroundsd $11, %xmm0, %xmm0, %xmm1
+; AVX-NEXT: vcmpneqsd %xmm0, %xmm1, %xmm0
; AVX-NEXT: vmovd %xmm0, %eax
; AVX-NEXT: andl $1, %eax
; AVX-NEXT: # kill: def $al killed $al killed $eax
-; AVX-NEXT: movl %ebp, %esp
-; AVX-NEXT: popl %ebp
; AVX-NEXT: retl
;
; AVX512-LABEL: une_f64_i64:
; AVX512: # %bb.0: # %entry
; AVX512-NEXT: vmovsd {{.*#+}} xmm0 = mem[0],zero
-; AVX512-NEXT: vcvttpd2qq %xmm0, %xmm1
-; AVX512-NEXT: vcvtqq2pd %ymm1, %ymm1
+; AVX512-NEXT: vroundsd $11, %xmm0, %xmm0, %xmm1
; AVX512-NEXT: vcmpneqsd %xmm0, %xmm1, %k0
; AVX512-NEXT: kmovd %k0, %eax
; AVX512-NEXT: # kill: def $al killed $al killed $eax
-; AVX512-NEXT: vzeroupper
; AVX512-NEXT: retl
entry:
%0 = fptosi double %x to i64
@@ -480,48 +401,21 @@ define zeroext i8 @une_f64_u64(double %x) nounwind readnone {
;
; AVX-LABEL: une_f64_u64:
; AVX: # %bb.0: # %entry
-; AVX-NEXT: pushl %ebp
-; AVX-NEXT: movl %esp, %ebp
-; AVX-NEXT: andl $-8, %esp
-; AVX-NEXT: subl $8, %esp
; AVX-NEXT: vmovsd {{.*#+}} xmm0 = mem[0],zero
-; AVX-NEXT: vmovsd {{.*#+}} xmm1 = [9.2233720368547758E+18,0.0E+0]
-; AVX-NEXT: vucomisd %xmm0, %xmm1
-; AVX-NEXT: jbe .LBB7_2
-; AVX-NEXT: # %bb.1: # %entry
-; AVX-NEXT: vxorpd %xmm1, %xmm1, %xmm1
-; AVX-NEXT: .LBB7_2: # %entry
-; AVX-NEXT: vsubsd %xmm1, %xmm0, %xmm1
-; AVX-NEXT: vmovsd %xmm1, (%esp)
-; AVX-NEXT: fldl (%esp)
-; AVX-NEXT: fisttpll (%esp)
-; AVX-NEXT: setbe %al
-; AVX-NEXT: movzbl %al, %eax
-; AVX-NEXT: shll $31, %eax
-; AVX-NEXT: xorl {{[0-9]+}}(%esp), %eax
-; AVX-NEXT: vmovd {{.*#+}} xmm1 = mem[0],zero,zero,zero
-; AVX-NEXT: vpinsrd $1, %eax, %xmm1, %xmm1
-; AVX-NEXT: vpunpckldq {{.*#+}} xmm1 = xmm1[0],mem[0],xmm1[1],mem[1]
-; AVX-NEXT: vsubpd {{\.?LCPI[0-9]+_[0-9]+}}, %xmm1, %xmm1
-; AVX-NEXT: vshufpd {{.*#+}} xmm2 = xmm1[1,0]
-; AVX-NEXT: vaddsd %xmm1, %xmm2, %xmm1
+; AVX-NEXT: vroundsd $11, %xmm0, %xmm0, %xmm1
; AVX-NEXT: vcmpneqsd %xmm0, %xmm1, %xmm0
; AVX-NEXT: vmovd %xmm0, %eax
; AVX-NEXT: andl $1, %eax
; AVX-NEXT: # kill: def $al killed $al killed $eax
-; AVX-NEXT: movl %ebp, %esp
-; AVX-NEXT: popl %ebp
; AVX-NEXT: retl
;
; AVX512-LABEL: une_f64_u64:
; AVX512: # %bb.0: # %entry
; AVX512-NEXT: vmovsd {{.*#+}} xmm0 = mem[0],zero
-; AVX512-NEXT: vcvttpd2uqq %xmm0, %xmm1
-; AVX512-NEXT: vcvtuqq2pd %ymm1, %ymm1
+; AVX512-NEXT: vroundsd $11, %xmm0, %xmm0, %xmm1
; AVX512-NEXT: vcmpneqsd %xmm0, %xmm1, %k0
; AVX512-NEXT: kmovd %k0, %eax
; AVX512-NEXT: # kill: def $al killed $al killed $eax
-; AVX512-NEXT: vzeroupper
; AVX512-NEXT: retl
entry:
%0 = fptoui double %x to i64
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