[llvm] [X86] lowerFPToIntToFP - handle UI2FP on AVX512VL targets and i64 types on AVX512DQ targets (PR #162656)

Kavin Gnanapandithan via llvm-commits llvm-commits at lists.llvm.org
Thu Oct 9 06:37:53 PDT 2025


https://github.com/KavinTheG created https://github.com/llvm/llvm-project/pull/162656

fixes llvm#160111

>From a45fcc9195e6a52d430420f4207a3d9d15ed0f18 Mon Sep 17 00:00:00 2001
From: Kavin Gnanapandithan <kavin.balag at gmail.com>
Date: Thu, 9 Oct 2025 08:41:07 -0400
Subject: [PATCH 1/2] Added AVX512 handling for UI2P in lowerFPToIntToFP

---
 llvm/lib/Target/X86/X86ISelLowering.cpp |  66 +++-
 llvm/test/CodeGen/X86/isint.ll          | 459 +++++++++++++++++++++++-
 2 files changed, 508 insertions(+), 17 deletions(-)

diff --git a/llvm/lib/Target/X86/X86ISelLowering.cpp b/llvm/lib/Target/X86/X86ISelLowering.cpp
index 2feb76e0eb7b4..9e209405bf99e 100644
--- a/llvm/lib/Target/X86/X86ISelLowering.cpp
+++ b/llvm/lib/Target/X86/X86ISelLowering.cpp
@@ -19885,7 +19885,7 @@ static SDValue lowerFPToIntToFP(SDValue CastToFP, const SDLoc &DL,
   // TODO: Allow FP_TO_UINT.
   SDValue CastToInt = CastToFP.getOperand(0);
   MVT VT = CastToFP.getSimpleValueType();
-  if (CastToInt.getOpcode() != ISD::FP_TO_SINT || VT.isVector())
+  if ((CastToInt.getOpcode() != ISD::FP_TO_SINT && CastToInt.getOpcode() != ISD::FP_TO_UINT) || VT.isVector())
     return SDValue();
 
   MVT IntVT = CastToInt.getSimpleValueType();
@@ -19897,22 +19897,68 @@ static SDValue lowerFPToIntToFP(SDValue CastToFP, const SDLoc &DL,
   // See if we have 128-bit vector cast instructions for this type of cast.
   // We need cvttps2dq/cvttpd2dq and cvtdq2ps/cvtdq2pd.
   if (!Subtarget.hasSSE2() || (VT != MVT::f32 && VT != MVT::f64) ||
-      IntVT != MVT::i32)
+      !(IntVT == MVT::i32 || (IntVT == MVT::i64 && Subtarget.hasDQI())))
     return SDValue();
 
   unsigned SrcSize = SrcVT.getSizeInBits();
   unsigned IntSize = IntVT.getSizeInBits();
   unsigned VTSize = VT.getSizeInBits();
-  MVT VecSrcVT = MVT::getVectorVT(SrcVT, 128 / SrcSize);
-  MVT VecIntVT = MVT::getVectorVT(IntVT, 128 / IntSize);
-  MVT VecVT = MVT::getVectorVT(VT, 128 / VTSize);
+  unsigned ToIntOpcode, ToFPOpcode;
+  unsigned Width = 128;
+  bool IsUnsigned = CastToInt.getOpcode() == ISD::FP_TO_UINT;
 
-  // We need target-specific opcodes if this is v2f64 -> v4i32 -> v2f64.
-  unsigned ToIntOpcode =
-      SrcSize != IntSize ? X86ISD::CVTTP2SI : (unsigned)ISD::FP_TO_SINT;
-  unsigned ToFPOpcode =
-      IntSize != VTSize ? X86ISD::CVTSI2P : (unsigned)ISD::SINT_TO_FP;
+  if (IntVT == MVT::i32) {
+    if (IsUnsigned && !Subtarget.hasVLX())
+      return SDValue(); // Need AVX512VL for unsigned i32
 
+    if (Subtarget.hasVLX()) {
+      if (IsUnsigned) {
+        ToIntOpcode = SrcSize != IntSize ? X86ISD::CVTTP2UI : (unsigned)ISD::FP_TO_UINT;
+        ToFPOpcode = IntSize != VTSize ? X86ISD::CVTUI2P : (unsigned)ISD::UINT_TO_FP;
+      } else {
+        ToIntOpcode = SrcSize != IntSize ? X86ISD::CVTTP2SI : (unsigned)ISD::FP_TO_SINT;
+        ToFPOpcode = IntSize != VTSize ? X86ISD::CVTSI2P : (unsigned)ISD::SINT_TO_FP;
+      }
+     } else {
+      // SSE2
+      ToIntOpcode = SrcSize != IntSize ? X86ISD::CVTTP2SI : (unsigned)ISD::FP_TO_SINT;
+      ToFPOpcode = IntSize != VTSize ? X86ISD::CVTSI2P : (unsigned)ISD::SINT_TO_FP;
+    }
+  } else {
+    if (Subtarget.hasVLX()) {
+      if (IsUnsigned) {
+        ToIntOpcode = SrcSize != IntSize ? X86ISD::CVTTP2UI : (unsigned)ISD::FP_TO_UINT;
+        ToFPOpcode = IntSize != VTSize ? X86ISD::CVTUI2P : (unsigned)ISD::UINT_TO_FP;
+      } else {
+        ToIntOpcode = SrcSize != IntSize ? X86ISD::CVTTP2SI : (unsigned)ISD::FP_TO_SINT;
+        ToFPOpcode = IntSize != VTSize ? X86ISD::CVTSI2P : (unsigned)ISD::SINT_TO_FP;
+      }
+    } else {
+      // Need to extend width for AVX512DQ
+      Width = 512;
+      ToIntOpcode = CastToInt.getOpcode();
+      ToFPOpcode = IsUnsigned ? ISD::UINT_TO_FP : ISD::SINT_TO_FP;
+    }
+  }
+
+  MVT VecSrcVT; 
+  MVT VecIntVT;
+  MVT VecVT;
+  if (IntVT == MVT::i64) {
+    unsigned NumElts = Width / IntSize;
+    VecIntVT = MVT::getVectorVT(IntVT, NumElts);
+    
+    // minimum legal size is v4f32
+    unsigned SrcElts = (SrcVT == MVT::f32) ? std::max(NumElts, 4u) : NumElts;
+    unsigned VTElts = (VT == MVT::f32) ? std::max(NumElts, 4u) : NumElts;
+    
+    VecSrcVT = MVT::getVectorVT(SrcVT, SrcElts);
+    VecVT = MVT::getVectorVT(VT, VTElts); 
+  } else {
+    VecSrcVT = MVT::getVectorVT(SrcVT, Width / SrcSize);
+    VecIntVT = MVT::getVectorVT(IntVT, Width / IntSize);
+    VecVT = MVT::getVectorVT(VT, Width / VTSize);
+  }
   // sint_to_fp (fp_to_sint X) --> extelt (sint_to_fp (fp_to_sint (s2v X))), 0
   //
   // We are not defining the high elements (for example, zero them) because
diff --git a/llvm/test/CodeGen/X86/isint.ll b/llvm/test/CodeGen/X86/isint.ll
index 8a56f49a6c755..d0b340ce37875 100644
--- a/llvm/test/CodeGen/X86/isint.ll
+++ b/llvm/test/CodeGen/X86/isint.ll
@@ -1,7 +1,9 @@
 ; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
 ; RUN: llc < %s -mtriple=x86_64-pc-unknown -mattr=+sse2 | FileCheck -check-prefix=CHECK64 %s
 ; RUN: llc < %s -mtriple=i686-pc-unknown -mattr=+sse2 | FileCheck -check-prefix=CHECK32 %s
-
+; RUN: llc < %s -mtriple=x86_64-pc-unknown -mattr=+avx512f | FileCheck -check-prefix=AVX512-NODQ %s
+; RUN: llc < %s -mtriple=x86_64-pc-unknown -mattr=+avx512f,+avx512dq | FileCheck -check-prefix=AVX512-NODQ %s
+; RUN: llc < %s -mtriple=x86_64-pc-unknown -mattr=+avx512f,+avx512dq,+avx512vl | FileCheck -check-prefix=AVX512VL %s
 ; PR19059
 
 define i32 @isint_return(double %d) nounwind {
@@ -24,6 +26,22 @@ define i32 @isint_return(double %d) nounwind {
 ; CHECK32-NEXT:    movd %xmm1, %eax
 ; CHECK32-NEXT:    andl $1, %eax
 ; CHECK32-NEXT:    retl
+;
+; AVX512-NODQ-LABEL: isint_return:
+; AVX512-NODQ:       # %bb.0:
+; AVX512-NODQ-NEXT:    vcvttpd2dq %xmm0, %xmm1
+; AVX512-NODQ-NEXT:    vcvtdq2pd %xmm1, %xmm1
+; AVX512-NODQ-NEXT:    vcmpeqsd %xmm1, %xmm0, %k0
+; AVX512-NODQ-NEXT:    kmovw %k0, %eax
+; AVX512-NODQ-NEXT:    retq
+;
+; AVX512VL-LABEL: isint_return:
+; AVX512VL:       # %bb.0:
+; AVX512VL-NEXT:    vcvttpd2dq %xmm0, %xmm1
+; AVX512VL-NEXT:    vcvtdq2pd %xmm1, %xmm1
+; AVX512VL-NEXT:    vcmpeqsd %xmm1, %xmm0, %k0
+; AVX512VL-NEXT:    kmovw %k0, %eax
+; AVX512VL-NEXT:    retq
   %i = fptosi double %d to i32
   %e = sitofp i32 %i to double
   %c = fcmp oeq double %d, %e
@@ -50,6 +68,221 @@ define i32 @isint_float_return(float %f) nounwind {
 ; CHECK32-NEXT:    movd %xmm1, %eax
 ; CHECK32-NEXT:    andl $1, %eax
 ; CHECK32-NEXT:    retl
+;
+; AVX512-NODQ-LABEL: isint_float_return:
+; AVX512-NODQ:       # %bb.0:
+; AVX512-NODQ-NEXT:    vcvttps2dq %xmm0, %xmm1
+; AVX512-NODQ-NEXT:    vcvtdq2ps %xmm1, %xmm1
+; AVX512-NODQ-NEXT:    vcmpeqss %xmm1, %xmm0, %k0
+; AVX512-NODQ-NEXT:    kmovw %k0, %eax
+; AVX512-NODQ-NEXT:    retq
+;
+; AVX512VL-LABEL: isint_float_return:
+; AVX512VL:       # %bb.0:
+; AVX512VL-NEXT:    vcvttps2dq %xmm0, %xmm1
+; AVX512VL-NEXT:    vcvtdq2ps %xmm1, %xmm1
+; AVX512VL-NEXT:    vcmpeqss %xmm1, %xmm0, %k0
+; AVX512VL-NEXT:    kmovw %k0, %eax
+; AVX512VL-NEXT:    retq
+  %i = fptosi float %f to i32
+  %g = sitofp i32 %i to float
+  %c = fcmp oeq float %f, %g
+  %z = zext i1 %c to i32
+  ret i32 %z
+}
+
+define i64 @isint64_float_return(float %f) nounwind {
+; CHECK64-LABEL: isint64_float_return:
+; CHECK64:       # %bb.0:
+; CHECK64-NEXT:    cvttss2si %xmm0, %rax
+; CHECK64-NEXT:    cvtsi2ss %rax, %xmm1
+; CHECK64-NEXT:    cmpeqss %xmm0, %xmm1
+; CHECK64-NEXT:    movd %xmm1, %eax
+; CHECK64-NEXT:    andl $1, %eax
+; CHECK64-NEXT:    retq
+;
+; CHECK32-LABEL: isint64_float_return:
+; CHECK32:       # %bb.0:
+; CHECK32-NEXT:    pushl %ebp
+; CHECK32-NEXT:    movl %esp, %ebp
+; CHECK32-NEXT:    andl $-8, %esp
+; CHECK32-NEXT:    subl $32, %esp
+; CHECK32-NEXT:    movss {{.*#+}} xmm0 = mem[0],zero,zero,zero
+; CHECK32-NEXT:    movss %xmm0, {{[0-9]+}}(%esp)
+; CHECK32-NEXT:    flds {{[0-9]+}}(%esp)
+; CHECK32-NEXT:    fnstcw {{[0-9]+}}(%esp)
+; CHECK32-NEXT:    movzwl {{[0-9]+}}(%esp), %eax
+; CHECK32-NEXT:    orl $3072, %eax # imm = 0xC00
+; CHECK32-NEXT:    movw %ax, {{[0-9]+}}(%esp)
+; CHECK32-NEXT:    fldcw {{[0-9]+}}(%esp)
+; CHECK32-NEXT:    fistpll {{[0-9]+}}(%esp)
+; CHECK32-NEXT:    fldcw {{[0-9]+}}(%esp)
+; CHECK32-NEXT:    movsd {{.*#+}} xmm1 = mem[0],zero
+; CHECK32-NEXT:    movlps %xmm1, {{[0-9]+}}(%esp)
+; CHECK32-NEXT:    fildll {{[0-9]+}}(%esp)
+; CHECK32-NEXT:    fstps {{[0-9]+}}(%esp)
+; CHECK32-NEXT:    cmpeqss {{[0-9]+}}(%esp), %xmm0
+; CHECK32-NEXT:    movd %xmm0, %eax
+; CHECK32-NEXT:    andl $1, %eax
+; CHECK32-NEXT:    xorl %edx, %edx
+; CHECK32-NEXT:    movl %ebp, %esp
+; CHECK32-NEXT:    popl %ebp
+; CHECK32-NEXT:    retl
+;
+; AVX512VL-LABEL: isint64_float_return:
+; AVX512VL:       # %bb.0:
+; AVX512VL-NEXT:    vcvttps2qq %xmm0, %xmm1
+; AVX512VL-NEXT:    vcvtqq2ps %xmm1, %xmm1
+; AVX512VL-NEXT:    vcmpeqss %xmm1, %xmm0, %k0
+; AVX512VL-NEXT:    kmovw %k0, %eax
+; AVX512VL-NEXT:    retq
+  %i = fptosi float %f to i64
+  %g = sitofp i64 %i to float
+  %c = fcmp oeq float %f, %g
+  %z = zext i1 %c to i64
+  ret i64 %z
+}
+
+define i64 @isint64_return(double %d) nounwind {
+; CHECK64-LABEL: isint64_return:
+; CHECK64:       # %bb.0:
+; CHECK64-NEXT:    cvttsd2si %xmm0, %rax
+; CHECK64-NEXT:    cvtsi2sd %rax, %xmm1
+; CHECK64-NEXT:    cmpeqsd %xmm0, %xmm1
+; CHECK64-NEXT:    movq %xmm1, %rax
+; CHECK64-NEXT:    andl $1, %eax
+; CHECK64-NEXT:    retq
+;
+; CHECK32-LABEL: isint64_return:
+; CHECK32:       # %bb.0:
+; CHECK32-NEXT:    pushl %ebp
+; CHECK32-NEXT:    movl %esp, %ebp
+; CHECK32-NEXT:    andl $-8, %esp
+; CHECK32-NEXT:    subl $32, %esp
+; CHECK32-NEXT:    movsd {{.*#+}} xmm0 = mem[0],zero
+; CHECK32-NEXT:    movsd %xmm0, {{[0-9]+}}(%esp)
+; CHECK32-NEXT:    fldl {{[0-9]+}}(%esp)
+; CHECK32-NEXT:    fnstcw {{[0-9]+}}(%esp)
+; CHECK32-NEXT:    movzwl {{[0-9]+}}(%esp), %eax
+; CHECK32-NEXT:    orl $3072, %eax # imm = 0xC00
+; CHECK32-NEXT:    movw %ax, {{[0-9]+}}(%esp)
+; CHECK32-NEXT:    fldcw {{[0-9]+}}(%esp)
+; CHECK32-NEXT:    fistpll {{[0-9]+}}(%esp)
+; CHECK32-NEXT:    fldcw {{[0-9]+}}(%esp)
+; CHECK32-NEXT:    movsd {{.*#+}} xmm1 = mem[0],zero
+; CHECK32-NEXT:    movlps %xmm1, {{[0-9]+}}(%esp)
+; CHECK32-NEXT:    fildll {{[0-9]+}}(%esp)
+; CHECK32-NEXT:    fstpl {{[0-9]+}}(%esp)
+; CHECK32-NEXT:    cmpeqsd {{[0-9]+}}(%esp), %xmm0
+; CHECK32-NEXT:    movd %xmm0, %eax
+; CHECK32-NEXT:    andl $1, %eax
+; CHECK32-NEXT:    xorl %edx, %edx
+; CHECK32-NEXT:    movl %ebp, %esp
+; CHECK32-NEXT:    popl %ebp
+; CHECK32-NEXT:    retl
+;
+; AVX512VL-LABEL: isint64_return:
+; AVX512VL:       # %bb.0:
+; AVX512VL-NEXT:    vcvttpd2qq %xmm0, %xmm1
+; AVX512VL-NEXT:    vcvtqq2pd %xmm1, %xmm1
+; AVX512VL-NEXT:    vcmpeqsd %xmm1, %xmm0, %k0
+; AVX512VL-NEXT:    kmovw %k0, %eax
+; AVX512VL-NEXT:    retq
+  %i = fptosi double %d to i64
+  %g = sitofp i64 %i to double
+  %c = fcmp oeq double %d, %g
+  %z = zext i1 %c to i64
+  ret i64 %z
+}
+
+define i32 @isuint_return(double %d) nounwind {
+; CHECK64-LABEL: isuint_return:
+; CHECK64:       # %bb.0:
+; CHECK64-NEXT:    cvttsd2si %xmm0, %rax
+; CHECK64-NEXT:    movl %eax, %eax
+; CHECK64-NEXT:    cvtsi2sd %rax, %xmm1
+; CHECK64-NEXT:    cmpeqsd %xmm0, %xmm1
+; CHECK64-NEXT:    movq %xmm1, %rax
+; CHECK64-NEXT:    andl $1, %eax
+; CHECK64-NEXT:    # kill: def $eax killed $eax killed $rax
+; CHECK64-NEXT:    retq
+;
+; CHECK32-LABEL: isuint_return:
+; CHECK32:       # %bb.0:
+; CHECK32-NEXT:    movsd {{.*#+}} xmm0 = mem[0],zero
+; CHECK32-NEXT:    cvttsd2si %xmm0, %eax
+; CHECK32-NEXT:    movl %eax, %ecx
+; CHECK32-NEXT:    sarl $31, %ecx
+; CHECK32-NEXT:    movapd %xmm0, %xmm1
+; CHECK32-NEXT:    subsd {{\.?LCPI[0-9]+_[0-9]+}}, %xmm1
+; CHECK32-NEXT:    cvttsd2si %xmm1, %edx
+; CHECK32-NEXT:    andl %ecx, %edx
+; CHECK32-NEXT:    orl %eax, %edx
+; CHECK32-NEXT:    movd %edx, %xmm1
+; CHECK32-NEXT:    por {{\.?LCPI[0-9]+_[0-9]+}}, %xmm1
+; CHECK32-NEXT:    subsd {{\.?LCPI[0-9]+_[0-9]+}}, %xmm1
+; CHECK32-NEXT:    cmpeqsd %xmm0, %xmm1
+; CHECK32-NEXT:    movd %xmm1, %eax
+; CHECK32-NEXT:    andl $1, %eax
+; CHECK32-NEXT:    retl
+;
+; AVX512-NODQ-LABEL: isuint_return:
+; AVX512-NODQ:       # %bb.0:
+; AVX512-NODQ-NEXT:    vcvttsd2usi %xmm0, %eax
+; AVX512-NODQ-NEXT:    vcvtusi2sd %eax, %xmm15, %xmm1
+; AVX512-NODQ-NEXT:    vcmpeqsd %xmm1, %xmm0, %k0
+; AVX512-NODQ-NEXT:    kmovw %k0, %eax
+; AVX512-NODQ-NEXT:    retq
+;
+; AVX512VL-LABEL: isuint_return:
+; AVX512VL:       # %bb.0:
+; AVX512VL-NEXT:    vcvttsd2usi %xmm0, %eax
+; AVX512VL-NEXT:    vcvtusi2sd %eax, %xmm15, %xmm1
+; AVX512VL-NEXT:    vcmpeqsd %xmm1, %xmm0, %k0
+; AVX512VL-NEXT:    kmovw %k0, %eax
+; AVX512VL-NEXT:    retq
+  %i = fptoui double %d to i32
+  %e = uitofp i32 %i to double
+  %c = fcmp oeq double %d, %e
+  %z = zext i1 %c to i32
+  ret i32 %z
+}
+
+define i32 @isuint_float_return(float %f) nounwind {
+; CHECK64-LABEL: isuint_float_return:
+; CHECK64:       # %bb.0:
+; CHECK64-NEXT:    cvttps2dq %xmm0, %xmm1
+; CHECK64-NEXT:    cvtdq2ps %xmm1, %xmm1
+; CHECK64-NEXT:    cmpeqss %xmm0, %xmm1
+; CHECK64-NEXT:    movd %xmm1, %eax
+; CHECK64-NEXT:    andl $1, %eax
+; CHECK64-NEXT:    retq
+;
+; CHECK32-LABEL: isuint_float_return:
+; CHECK32:       # %bb.0:
+; CHECK32-NEXT:    movss {{.*#+}} xmm0 = mem[0],zero,zero,zero
+; CHECK32-NEXT:    cvttps2dq %xmm0, %xmm1
+; CHECK32-NEXT:    cvtdq2ps %xmm1, %xmm1
+; CHECK32-NEXT:    cmpeqss %xmm0, %xmm1
+; CHECK32-NEXT:    movd %xmm1, %eax
+; CHECK32-NEXT:    andl $1, %eax
+; CHECK32-NEXT:    retl
+;
+; AVX512-NODQ-LABEL: isuint_float_return:
+; AVX512-NODQ:       # %bb.0:
+; AVX512-NODQ-NEXT:    vcvttps2dq %xmm0, %xmm1
+; AVX512-NODQ-NEXT:    vcvtdq2ps %xmm1, %xmm1
+; AVX512-NODQ-NEXT:    vcmpeqss %xmm1, %xmm0, %k0
+; AVX512-NODQ-NEXT:    kmovw %k0, %eax
+; AVX512-NODQ-NEXT:    retq
+;
+; AVX512VL-LABEL: isuint_float_return:
+; AVX512VL:       # %bb.0:
+; AVX512VL-NEXT:    vcvttps2dq %xmm0, %xmm1
+; AVX512VL-NEXT:    vcvtdq2ps %xmm1, %xmm1
+; AVX512VL-NEXT:    vcmpeqss %xmm1, %xmm0, %k0
+; AVX512VL-NEXT:    kmovw %k0, %eax
+; AVX512VL-NEXT:    retq
   %i = fptosi float %f to i32
   %g = sitofp i32 %i to float
   %c = fcmp oeq float %f, %g
@@ -57,6 +290,190 @@ define i32 @isint_float_return(float %f) nounwind {
   ret i32 %z
 }
 
+define i64 @isuint64_return(double %d) nounwind {
+; CHECK64-LABEL: isuint64_return:
+; CHECK64:       # %bb.0:
+; CHECK64-NEXT:    cvttsd2si %xmm0, %rax
+; CHECK64-NEXT:    movq %rax, %rcx
+; CHECK64-NEXT:    sarq $63, %rcx
+; CHECK64-NEXT:    movapd %xmm0, %xmm1
+; CHECK64-NEXT:    subsd {{\.?LCPI[0-9]+_[0-9]+}}(%rip), %xmm1
+; CHECK64-NEXT:    cvttsd2si %xmm1, %rdx
+; CHECK64-NEXT:    andq %rcx, %rdx
+; CHECK64-NEXT:    orq %rax, %rdx
+; CHECK64-NEXT:    movq %rdx, %xmm1
+; CHECK64-NEXT:    punpckldq {{.*#+}} xmm1 = xmm1[0],mem[0],xmm1[1],mem[1]
+; CHECK64-NEXT:    subpd {{\.?LCPI[0-9]+_[0-9]+}}(%rip), %xmm1
+; CHECK64-NEXT:    movapd %xmm1, %xmm2
+; CHECK64-NEXT:    unpckhpd {{.*#+}} xmm2 = xmm2[1],xmm1[1]
+; CHECK64-NEXT:    addsd %xmm1, %xmm2
+; CHECK64-NEXT:    cmpeqsd %xmm0, %xmm2
+; CHECK64-NEXT:    movq %xmm2, %rax
+; CHECK64-NEXT:    andl $1, %eax
+; CHECK64-NEXT:    retq
+;
+; CHECK32-LABEL: isuint64_return:
+; CHECK32:       # %bb.0:
+; CHECK32-NEXT:    pushl %ebp
+; CHECK32-NEXT:    movl %esp, %ebp
+; CHECK32-NEXT:    andl $-8, %esp
+; CHECK32-NEXT:    subl $16, %esp
+; CHECK32-NEXT:    movsd {{.*#+}} xmm0 = mem[0],zero
+; CHECK32-NEXT:    movsd {{.*#+}} xmm1 = [9.2233720368547758E+18,0.0E+0]
+; CHECK32-NEXT:    ucomisd %xmm0, %xmm1
+; CHECK32-NEXT:    jbe .LBB6_2
+; CHECK32-NEXT:  # %bb.1:
+; CHECK32-NEXT:    xorpd %xmm1, %xmm1
+; CHECK32-NEXT:  .LBB6_2:
+; CHECK32-NEXT:    movapd %xmm0, %xmm2
+; CHECK32-NEXT:    subsd %xmm1, %xmm2
+; CHECK32-NEXT:    movsd %xmm2, {{[0-9]+}}(%esp)
+; CHECK32-NEXT:    setbe %al
+; CHECK32-NEXT:    fldl {{[0-9]+}}(%esp)
+; CHECK32-NEXT:    fnstcw {{[0-9]+}}(%esp)
+; CHECK32-NEXT:    movzwl {{[0-9]+}}(%esp), %ecx
+; CHECK32-NEXT:    orl $3072, %ecx # imm = 0xC00
+; CHECK32-NEXT:    movw %cx, {{[0-9]+}}(%esp)
+; CHECK32-NEXT:    fldcw {{[0-9]+}}(%esp)
+; CHECK32-NEXT:    fistpll {{[0-9]+}}(%esp)
+; CHECK32-NEXT:    fldcw {{[0-9]+}}(%esp)
+; CHECK32-NEXT:    movzbl %al, %eax
+; CHECK32-NEXT:    shll $31, %eax
+; CHECK32-NEXT:    xorl {{[0-9]+}}(%esp), %eax
+; CHECK32-NEXT:    movd %eax, %xmm1
+; CHECK32-NEXT:    movd {{.*#+}} xmm2 = mem[0],zero,zero,zero
+; CHECK32-NEXT:    punpckldq {{.*#+}} xmm2 = xmm2[0],xmm1[0],xmm2[1],xmm1[1]
+; CHECK32-NEXT:    punpckldq {{.*#+}} xmm2 = xmm2[0],mem[0],xmm2[1],mem[1]
+; CHECK32-NEXT:    subpd {{\.?LCPI[0-9]+_[0-9]+}}, %xmm2
+; CHECK32-NEXT:    movapd %xmm2, %xmm1
+; CHECK32-NEXT:    unpckhpd {{.*#+}} xmm1 = xmm1[1],xmm2[1]
+; CHECK32-NEXT:    addsd %xmm2, %xmm1
+; CHECK32-NEXT:    cmpeqsd %xmm0, %xmm1
+; CHECK32-NEXT:    movd %xmm1, %eax
+; CHECK32-NEXT:    andl $1, %eax
+; CHECK32-NEXT:    xorl %edx, %edx
+; CHECK32-NEXT:    movl %ebp, %esp
+; CHECK32-NEXT:    popl %ebp
+; CHECK32-NEXT:    retl
+;
+; AVX512-NODQ-LABEL: isuint64_return:
+; AVX512-NODQ:       # %bb.0:
+; AVX512-NODQ-NEXT:    vcvttsd2usi %xmm0, %rax
+; AVX512-NODQ-NEXT:    vcvtusi2sd %rax, %xmm15, %xmm1
+; AVX512-NODQ-NEXT:    vcmpeqsd %xmm1, %xmm0, %k0
+; AVX512-NODQ-NEXT:    kmovw %k0, %eax
+; AVX512-NODQ-NEXT:    retq
+;
+; AVX512VL-LABEL: isuint64_return:
+; AVX512VL:       # %bb.0:
+; AVX512VL-NEXT:    vcvttsd2usi %xmm0, %rax
+; AVX512VL-NEXT:    vcvtusi2sd %rax, %xmm15, %xmm1
+; AVX512VL-NEXT:    vcmpeqsd %xmm1, %xmm0, %k0
+; AVX512VL-NEXT:    kmovw %k0, %eax
+; AVX512VL-NEXT:    retq
+  %i = fptoui double %d to i64
+  %e = uitofp i64 %i to double
+  %c = fcmp oeq double %d, %e
+  %z = zext i1 %c to i64
+  ret i64 %z
+}
+
+define i64 @isuint64_float_return(float %f) nounwind {
+; CHECK64-LABEL: isuint64_float_return:
+; CHECK64:       # %bb.0:
+; CHECK64-NEXT:    cvttss2si %xmm0, %rcx
+; CHECK64-NEXT:    movq %rcx, %rdx
+; CHECK64-NEXT:    sarq $63, %rdx
+; CHECK64-NEXT:    movaps %xmm0, %xmm1
+; CHECK64-NEXT:    subss {{\.?LCPI[0-9]+_[0-9]+}}(%rip), %xmm1
+; CHECK64-NEXT:    cvttss2si %xmm1, %rax
+; CHECK64-NEXT:    andq %rdx, %rax
+; CHECK64-NEXT:    orq %rcx, %rax
+; CHECK64-NEXT:    js .LBB7_1
+; CHECK64-NEXT:  # %bb.2:
+; CHECK64-NEXT:    xorps %xmm1, %xmm1
+; CHECK64-NEXT:    cvtsi2ss %rax, %xmm1
+; CHECK64-NEXT:    jmp .LBB7_3
+; CHECK64-NEXT:  .LBB7_1:
+; CHECK64-NEXT:    movq %rax, %rcx
+; CHECK64-NEXT:    shrq %rcx
+; CHECK64-NEXT:    andl $1, %eax
+; CHECK64-NEXT:    orq %rcx, %rax
+; CHECK64-NEXT:    xorps %xmm1, %xmm1
+; CHECK64-NEXT:    cvtsi2ss %rax, %xmm1
+; CHECK64-NEXT:    addss %xmm1, %xmm1
+; CHECK64-NEXT:  .LBB7_3:
+; CHECK64-NEXT:    cmpeqss %xmm1, %xmm0
+; CHECK64-NEXT:    movd %xmm0, %eax
+; CHECK64-NEXT:    andl $1, %eax
+; CHECK64-NEXT:    retq
+;
+; CHECK32-LABEL: isuint64_float_return:
+; CHECK32:       # %bb.0:
+; CHECK32-NEXT:    pushl %ebp
+; CHECK32-NEXT:    movl %esp, %ebp
+; CHECK32-NEXT:    andl $-8, %esp
+; CHECK32-NEXT:    subl $32, %esp
+; CHECK32-NEXT:    movss {{.*#+}} xmm0 = mem[0],zero,zero,zero
+; CHECK32-NEXT:    movss {{.*#+}} xmm1 = [9.22337203E+18,0.0E+0,0.0E+0,0.0E+0]
+; CHECK32-NEXT:    ucomiss %xmm0, %xmm1
+; CHECK32-NEXT:    jbe .LBB7_2
+; CHECK32-NEXT:  # %bb.1:
+; CHECK32-NEXT:    xorps %xmm1, %xmm1
+; CHECK32-NEXT:  .LBB7_2:
+; CHECK32-NEXT:    movaps %xmm0, %xmm2
+; CHECK32-NEXT:    subss %xmm1, %xmm2
+; CHECK32-NEXT:    movss %xmm2, {{[0-9]+}}(%esp)
+; CHECK32-NEXT:    setbe %al
+; CHECK32-NEXT:    flds {{[0-9]+}}(%esp)
+; CHECK32-NEXT:    fnstcw {{[0-9]+}}(%esp)
+; CHECK32-NEXT:    movzwl {{[0-9]+}}(%esp), %ecx
+; CHECK32-NEXT:    orl $3072, %ecx # imm = 0xC00
+; CHECK32-NEXT:    movw %cx, {{[0-9]+}}(%esp)
+; CHECK32-NEXT:    fldcw {{[0-9]+}}(%esp)
+; CHECK32-NEXT:    fistpll {{[0-9]+}}(%esp)
+; CHECK32-NEXT:    fldcw {{[0-9]+}}(%esp)
+; CHECK32-NEXT:    movzbl %al, %eax
+; CHECK32-NEXT:    shll $31, %eax
+; CHECK32-NEXT:    xorl {{[0-9]+}}(%esp), %eax
+; CHECK32-NEXT:    movd %eax, %xmm1
+; CHECK32-NEXT:    movd {{.*#+}} xmm2 = mem[0],zero,zero,zero
+; CHECK32-NEXT:    punpckldq {{.*#+}} xmm2 = xmm2[0],xmm1[0],xmm2[1],xmm1[1]
+; CHECK32-NEXT:    movq %xmm2, {{[0-9]+}}(%esp)
+; CHECK32-NEXT:    shrl $31, %eax
+; CHECK32-NEXT:    fildll {{[0-9]+}}(%esp)
+; CHECK32-NEXT:    fadds {{\.?LCPI[0-9]+_[0-9]+}}(,%eax,4)
+; CHECK32-NEXT:    fstps {{[0-9]+}}(%esp)
+; CHECK32-NEXT:    cmpeqss {{[0-9]+}}(%esp), %xmm0
+; CHECK32-NEXT:    movd %xmm0, %eax
+; CHECK32-NEXT:    andl $1, %eax
+; CHECK32-NEXT:    xorl %edx, %edx
+; CHECK32-NEXT:    movl %ebp, %esp
+; CHECK32-NEXT:    popl %ebp
+; CHECK32-NEXT:    retl
+;
+; AVX512-NODQ-LABEL: isuint64_float_return:
+; AVX512-NODQ:       # %bb.0:
+; AVX512-NODQ-NEXT:    vcvttss2usi %xmm0, %rax
+; AVX512-NODQ-NEXT:    vcvtusi2ss %rax, %xmm15, %xmm1
+; AVX512-NODQ-NEXT:    vcmpeqss %xmm1, %xmm0, %k0
+; AVX512-NODQ-NEXT:    kmovw %k0, %eax
+; AVX512-NODQ-NEXT:    retq
+;
+; AVX512VL-LABEL: isuint64_float_return:
+; AVX512VL:       # %bb.0:
+; AVX512VL-NEXT:    vcvttss2usi %xmm0, %rax
+; AVX512VL-NEXT:    vcvtusi2ss %rax, %xmm15, %xmm1
+; AVX512VL-NEXT:    vcmpeqss %xmm1, %xmm0, %k0
+; AVX512VL-NEXT:    kmovw %k0, %eax
+; AVX512VL-NEXT:    retq
+  %i = fptoui float %f to i64
+  %g = uitofp i64 %i to float
+  %c = fcmp oeq float %f, %g
+  %z = zext i1 %c to i64
+  ret i64 %z
+}
+
 declare void @foo()
 
 define void @isint_branch(double %d) nounwind {
@@ -65,13 +482,13 @@ define void @isint_branch(double %d) nounwind {
 ; CHECK64-NEXT:    cvttpd2dq %xmm0, %xmm1
 ; CHECK64-NEXT:    cvtdq2pd %xmm1, %xmm1
 ; CHECK64-NEXT:    ucomisd %xmm1, %xmm0
-; CHECK64-NEXT:    jne .LBB2_2
-; CHECK64-NEXT:    jp .LBB2_2
+; CHECK64-NEXT:    jne .LBB8_2
+; CHECK64-NEXT:    jp .LBB8_2
 ; CHECK64-NEXT:  # %bb.1: # %true
 ; CHECK64-NEXT:    pushq %rax
 ; CHECK64-NEXT:    callq foo at PLT
 ; CHECK64-NEXT:    popq %rax
-; CHECK64-NEXT:  .LBB2_2: # %false
+; CHECK64-NEXT:  .LBB8_2: # %false
 ; CHECK64-NEXT:    retq
 ;
 ; CHECK32-LABEL: isint_branch:
@@ -80,12 +497,40 @@ define void @isint_branch(double %d) nounwind {
 ; CHECK32-NEXT:    cvttpd2dq %xmm0, %xmm1
 ; CHECK32-NEXT:    cvtdq2pd %xmm1, %xmm1
 ; CHECK32-NEXT:    ucomisd %xmm1, %xmm0
-; CHECK32-NEXT:    jne .LBB2_2
-; CHECK32-NEXT:    jp .LBB2_2
+; CHECK32-NEXT:    jne .LBB8_2
+; CHECK32-NEXT:    jp .LBB8_2
 ; CHECK32-NEXT:  # %bb.1: # %true
 ; CHECK32-NEXT:    calll foo at PLT
-; CHECK32-NEXT:  .LBB2_2: # %false
+; CHECK32-NEXT:  .LBB8_2: # %false
 ; CHECK32-NEXT:    retl
+;
+; AVX512-NODQ-LABEL: isint_branch:
+; AVX512-NODQ:       # %bb.0:
+; AVX512-NODQ-NEXT:    vcvttpd2dq %xmm0, %xmm1
+; AVX512-NODQ-NEXT:    vcvtdq2pd %xmm1, %xmm1
+; AVX512-NODQ-NEXT:    vucomisd %xmm1, %xmm0
+; AVX512-NODQ-NEXT:    jne .LBB8_2
+; AVX512-NODQ-NEXT:    jp .LBB8_2
+; AVX512-NODQ-NEXT:  # %bb.1: # %true
+; AVX512-NODQ-NEXT:    pushq %rax
+; AVX512-NODQ-NEXT:    callq foo at PLT
+; AVX512-NODQ-NEXT:    popq %rax
+; AVX512-NODQ-NEXT:  .LBB8_2: # %false
+; AVX512-NODQ-NEXT:    retq
+;
+; AVX512VL-LABEL: isint_branch:
+; AVX512VL:       # %bb.0:
+; AVX512VL-NEXT:    vcvttpd2dq %xmm0, %xmm1
+; AVX512VL-NEXT:    vcvtdq2pd %xmm1, %xmm1
+; AVX512VL-NEXT:    vucomisd %xmm1, %xmm0
+; AVX512VL-NEXT:    jne .LBB8_2
+; AVX512VL-NEXT:    jp .LBB8_2
+; AVX512VL-NEXT:  # %bb.1: # %true
+; AVX512VL-NEXT:    pushq %rax
+; AVX512VL-NEXT:    callq foo at PLT
+; AVX512VL-NEXT:    popq %rax
+; AVX512VL-NEXT:  .LBB8_2: # %false
+; AVX512VL-NEXT:    retq
   %i = fptosi double %d to i32
   %e = sitofp i32 %i to double
   %c = fcmp oeq double %d, %e

>From b7f1545f29a61ca9cd1b2bf78ba134329c2709af Mon Sep 17 00:00:00 2001
From: Kavin Gnanapandithan <kavin.balag at gmail.com>
Date: Thu, 9 Oct 2025 09:07:02 -0400
Subject: [PATCH 2/2] Formatted lowerFPToIntToFP using git clang-format

---
 llvm/lib/Target/X86/X86ISelLowering.cpp | 44 ++++++++++++++++---------
 1 file changed, 28 insertions(+), 16 deletions(-)

diff --git a/llvm/lib/Target/X86/X86ISelLowering.cpp b/llvm/lib/Target/X86/X86ISelLowering.cpp
index 9e209405bf99e..946dbf8361aaf 100644
--- a/llvm/lib/Target/X86/X86ISelLowering.cpp
+++ b/llvm/lib/Target/X86/X86ISelLowering.cpp
@@ -19885,7 +19885,9 @@ static SDValue lowerFPToIntToFP(SDValue CastToFP, const SDLoc &DL,
   // TODO: Allow FP_TO_UINT.
   SDValue CastToInt = CastToFP.getOperand(0);
   MVT VT = CastToFP.getSimpleValueType();
-  if ((CastToInt.getOpcode() != ISD::FP_TO_SINT && CastToInt.getOpcode() != ISD::FP_TO_UINT) || VT.isVector())
+  if ((CastToInt.getOpcode() != ISD::FP_TO_SINT &&
+       CastToInt.getOpcode() != ISD::FP_TO_UINT) ||
+      VT.isVector())
     return SDValue();
 
   MVT IntVT = CastToInt.getSimpleValueType();
@@ -19913,25 +19915,35 @@ static SDValue lowerFPToIntToFP(SDValue CastToFP, const SDLoc &DL,
 
     if (Subtarget.hasVLX()) {
       if (IsUnsigned) {
-        ToIntOpcode = SrcSize != IntSize ? X86ISD::CVTTP2UI : (unsigned)ISD::FP_TO_UINT;
-        ToFPOpcode = IntSize != VTSize ? X86ISD::CVTUI2P : (unsigned)ISD::UINT_TO_FP;
+        ToIntOpcode =
+            SrcSize != IntSize ? X86ISD::CVTTP2UI : (unsigned)ISD::FP_TO_UINT;
+        ToFPOpcode =
+            IntSize != VTSize ? X86ISD::CVTUI2P : (unsigned)ISD::UINT_TO_FP;
       } else {
-        ToIntOpcode = SrcSize != IntSize ? X86ISD::CVTTP2SI : (unsigned)ISD::FP_TO_SINT;
-        ToFPOpcode = IntSize != VTSize ? X86ISD::CVTSI2P : (unsigned)ISD::SINT_TO_FP;
+        ToIntOpcode =
+            SrcSize != IntSize ? X86ISD::CVTTP2SI : (unsigned)ISD::FP_TO_SINT;
+        ToFPOpcode =
+            IntSize != VTSize ? X86ISD::CVTSI2P : (unsigned)ISD::SINT_TO_FP;
       }
-     } else {
+    } else {
       // SSE2
-      ToIntOpcode = SrcSize != IntSize ? X86ISD::CVTTP2SI : (unsigned)ISD::FP_TO_SINT;
-      ToFPOpcode = IntSize != VTSize ? X86ISD::CVTSI2P : (unsigned)ISD::SINT_TO_FP;
+      ToIntOpcode =
+          SrcSize != IntSize ? X86ISD::CVTTP2SI : (unsigned)ISD::FP_TO_SINT;
+      ToFPOpcode =
+          IntSize != VTSize ? X86ISD::CVTSI2P : (unsigned)ISD::SINT_TO_FP;
     }
   } else {
     if (Subtarget.hasVLX()) {
       if (IsUnsigned) {
-        ToIntOpcode = SrcSize != IntSize ? X86ISD::CVTTP2UI : (unsigned)ISD::FP_TO_UINT;
-        ToFPOpcode = IntSize != VTSize ? X86ISD::CVTUI2P : (unsigned)ISD::UINT_TO_FP;
+        ToIntOpcode =
+            SrcSize != IntSize ? X86ISD::CVTTP2UI : (unsigned)ISD::FP_TO_UINT;
+        ToFPOpcode =
+            IntSize != VTSize ? X86ISD::CVTUI2P : (unsigned)ISD::UINT_TO_FP;
       } else {
-        ToIntOpcode = SrcSize != IntSize ? X86ISD::CVTTP2SI : (unsigned)ISD::FP_TO_SINT;
-        ToFPOpcode = IntSize != VTSize ? X86ISD::CVTSI2P : (unsigned)ISD::SINT_TO_FP;
+        ToIntOpcode =
+            SrcSize != IntSize ? X86ISD::CVTTP2SI : (unsigned)ISD::FP_TO_SINT;
+        ToFPOpcode =
+            IntSize != VTSize ? X86ISD::CVTSI2P : (unsigned)ISD::SINT_TO_FP;
       }
     } else {
       // Need to extend width for AVX512DQ
@@ -19941,19 +19953,19 @@ static SDValue lowerFPToIntToFP(SDValue CastToFP, const SDLoc &DL,
     }
   }
 
-  MVT VecSrcVT; 
+  MVT VecSrcVT;
   MVT VecIntVT;
   MVT VecVT;
   if (IntVT == MVT::i64) {
     unsigned NumElts = Width / IntSize;
     VecIntVT = MVT::getVectorVT(IntVT, NumElts);
-    
+
     // minimum legal size is v4f32
     unsigned SrcElts = (SrcVT == MVT::f32) ? std::max(NumElts, 4u) : NumElts;
     unsigned VTElts = (VT == MVT::f32) ? std::max(NumElts, 4u) : NumElts;
-    
+
     VecSrcVT = MVT::getVectorVT(SrcVT, SrcElts);
-    VecVT = MVT::getVectorVT(VT, VTElts); 
+    VecVT = MVT::getVectorVT(VT, VTElts);
   } else {
     VecSrcVT = MVT::getVectorVT(SrcVT, Width / SrcSize);
     VecIntVT = MVT::getVectorVT(IntVT, Width / IntSize);



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