[llvm-branch-commits] [llvm] [X86] Cast atomic vectors in IR to support floats (PR #148899)

[via llvm-branch-commits]

https://github.com/jofrn updated https://github.com/llvm/llvm-project/pull/148899

>From 804de61af18b448a33005dd28566367f298e8d01 Mon Sep 17 00:00:00 2001
From: jofrn <jofernau at amd.com>
Date: Tue, 15 Jul 2025 13:02:04 -0400
Subject: [PATCH] [X86] Cast atomic vectors in IR to support floats

This commit casts floats to ints in an atomic load during AtomicExpand to support
floating point types. It also is required to support 128 bit vectors in SSE/AVX.
---
 llvm/lib/Target/X86/X86ISelLowering.cpp | 7 +++++++
 llvm/lib/Target/X86/X86ISelLowering.h   | 2 ++
 2 files changed, 9 insertions(+)

diff --git a/llvm/lib/Target/X86/X86ISelLowering.cpp b/llvm/lib/Target/X86/X86ISelLowering.cpp
index 5785440a20e43..15b828a17c451 100644
--- a/llvm/lib/Target/X86/X86ISelLowering.cpp
+++ b/llvm/lib/Target/X86/X86ISelLowering.cpp
@@ -32136,6 +32136,13 @@ X86TargetLowering::shouldExpandAtomicRMWInIR(AtomicRMWInst *AI) const {
   }
 }
 
+TargetLowering::AtomicExpansionKind
+X86TargetLowering::shouldCastAtomicLoadInIR(LoadInst *LI) const {
+  if (LI->getType()->getScalarType()->isFloatingPointTy())
+    return AtomicExpansionKind::CastToInteger;
+  return AtomicExpansionKind::None;
+}
+
 LoadInst *
 X86TargetLowering::lowerIdempotentRMWIntoFencedLoad(AtomicRMWInst *AI) const {
   unsigned NativeWidth = Subtarget.is64Bit() ? 64 : 32;
diff --git a/llvm/lib/Target/X86/X86ISelLowering.h b/llvm/lib/Target/X86/X86ISelLowering.h
index b7151f65942b4..f9a8adbd7da0d 100644
--- a/llvm/lib/Target/X86/X86ISelLowering.h
+++ b/llvm/lib/Target/X86/X86ISelLowering.h
@@ -1841,6 +1841,8 @@ namespace llvm {
     shouldExpandAtomicRMWInIR(AtomicRMWInst *AI) const override;
     TargetLoweringBase::AtomicExpansionKind
     shouldExpandLogicAtomicRMWInIR(AtomicRMWInst *AI) const;
+    TargetLoweringBase::AtomicExpansionKind
+    shouldCastAtomicLoadInIR(LoadInst *LI) const override;
     void emitBitTestAtomicRMWIntrinsic(AtomicRMWInst *AI) const override;
     void emitCmpArithAtomicRMWIntrinsic(AtomicRMWInst *AI) const override;