[llvm] [X86] vectorizeExtractedCast - don't assume vector source type is simple (PR #178414)

[Simon Pilgrim via llvm-commits]

https://github.com/RKSimon updated https://github.com/llvm/llvm-project/pull/178414

>From 46daed54d35c557b4f5a10c4f6ecdbc0b16f3172 Mon Sep 17 00:00:00 2001
From: Simon Pilgrim <llvm-dev at redking.me.uk>
Date: Wed, 28 Jan 2026 13:03:59 +0000
Subject: [PATCH 1/2] [X86] vectorizeExtractedCast - don't assume vector source
 type is simple

Fixes #178410
---
 llvm/lib/Target/X86/X86ISelLowering.cpp |  4 +--
 llvm/test/CodeGen/X86/pr178410.ll       | 38 +++++++++++++++++++++++++
 2 files changed, 40 insertions(+), 2 deletions(-)
 create mode 100644 llvm/test/CodeGen/X86/pr178410.ll

diff --git a/llvm/lib/Target/X86/X86ISelLowering.cpp b/llvm/lib/Target/X86/X86ISelLowering.cpp
index 1b3e0148262d6..5df7d4689fab2 100644
--- a/llvm/lib/Target/X86/X86ISelLowering.cpp
+++ b/llvm/lib/Target/X86/X86ISelLowering.cpp
@@ -20185,9 +20185,9 @@ static SDValue vectorizeExtractedCast(SDValue Cast, const SDLoc &DL,
 
   // See if we have a 128-bit vector cast op for this type of cast.
   SDValue VecOp = Extract.getOperand(0);
-  MVT FromVT = VecOp.getSimpleValueType();
+  EVT FromVT = VecOp.getValueType();
   unsigned NumEltsInXMM = 128 / FromVT.getScalarSizeInBits();
-  MVT Vec128VT = MVT::getVectorVT(FromVT.getScalarType(), NumEltsInXMM);
+  MVT Vec128VT = MVT::getVectorVT(FromVT.getScalarType().getSimpleVT(), NumEltsInXMM);
   MVT ToVT = MVT::getVectorVT(DestVT, NumEltsInXMM);
   if (!useVectorCast(Cast.getOpcode(), Vec128VT, ToVT, Subtarget))
     return SDValue();
diff --git a/llvm/test/CodeGen/X86/pr178410.ll b/llvm/test/CodeGen/X86/pr178410.ll
new file mode 100644
index 0000000000000..09be5428001e6
--- /dev/null
+++ b/llvm/test/CodeGen/X86/pr178410.ll
@@ -0,0 +1,38 @@
+; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py UTC_ARGS: --version 6
+; RUN: llc < %s -mtriple=i686-- | FileCheck %s --check-prefixes=X86
+; RUN: llc < %s -mtriple=x86_64-- -mcpu=x86-64    | FileCheck %s --check-prefixes=SSE
+; RUN: llc < %s -mtriple=x86_64-- -mcpu=x86-64-v2 | FileCheck %s --check-prefixes=SSE
+; RUN: llc < %s -mtriple=x86_64-- -mcpu=x86-64-v3 | FileCheck %s --check-prefixes=AVX
+; RUN: llc < %s -mtriple=x86_64-- -mcpu=x86-64-v4 | FileCheck %s --check-prefixes=AVX
+
+define float @PR178410(ptr %p0) nounwind {
+; X86-LABEL: PR178410:
+; X86:       # %bb.0:
+; X86-NEXT:    pushl %ebp
+; X86-NEXT:    movl %esp, %ebp
+; X86-NEXT:    andl $-8, %esp
+; X86-NEXT:    subl $8, %esp
+; X86-NEXT:    movl 8(%ebp), %eax
+; X86-NEXT:    movl (%eax), %ecx
+; X86-NEXT:    movl 4(%eax), %eax
+; X86-NEXT:    movl %eax, {{[0-9]+}}(%esp)
+; X86-NEXT:    movl %ecx, (%esp)
+; X86-NEXT:    fildll (%esp)
+; X86-NEXT:    movl %ebp, %esp
+; X86-NEXT:    popl %ebp
+; X86-NEXT:    retl
+;
+; SSE-LABEL: PR178410:
+; SSE:       # %bb.0:
+; SSE-NEXT:    cvtsi2ssq (%rdi), %xmm0
+; SSE-NEXT:    retq
+;
+; AVX-LABEL: PR178410:
+; AVX:       # %bb.0:
+; AVX-NEXT:    vcvtsi2ssq (%rdi), %xmm15, %xmm0
+; AVX-NEXT:    retq
+  %load = load <13 x i64>, ptr %p0, align 8
+  %elt = extractelement <13 x i64> %load, i64 0
+  %cvt = sitofp i64 %elt to float
+  ret float %cvt
+}

>From 19be057e41935192d0f2a179117d6601167e4bf6 Mon Sep 17 00:00:00 2001
From: Simon Pilgrim <llvm-dev at redking.me.uk>
Date: Wed, 28 Jan 2026 13:22:12 +0000
Subject: [PATCH 2/2] clang-format

---
 llvm/lib/Target/X86/X86ISelLowering.cpp | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/llvm/lib/Target/X86/X86ISelLowering.cpp b/llvm/lib/Target/X86/X86ISelLowering.cpp
index 5df7d4689fab2..ca73b336225f2 100644
--- a/llvm/lib/Target/X86/X86ISelLowering.cpp
+++ b/llvm/lib/Target/X86/X86ISelLowering.cpp
@@ -20187,7 +20187,8 @@ static SDValue vectorizeExtractedCast(SDValue Cast, const SDLoc &DL,
   SDValue VecOp = Extract.getOperand(0);
   EVT FromVT = VecOp.getValueType();
   unsigned NumEltsInXMM = 128 / FromVT.getScalarSizeInBits();
-  MVT Vec128VT = MVT::getVectorVT(FromVT.getScalarType().getSimpleVT(), NumEltsInXMM);
+  MVT Vec128VT =
+      MVT::getVectorVT(FromVT.getScalarType().getSimpleVT(), NumEltsInXMM);
   MVT ToVT = MVT::getVectorVT(DestVT, NumEltsInXMM);
   if (!useVectorCast(Cast.getOpcode(), Vec128VT, ToVT, Subtarget))
     return SDValue();