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[AArch64] Do not promote scalable constants to global variables #146926

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Merged
momchil-velikov merged 1 commit into from
Jul 7, 2025
Merged

[AArch64] Do not promote scalable constants to global variables #146926

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4 changes: 4 additions & 0 deletions llvm/lib/Target/AArch64/AArch64PromoteConstant.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -345,6 +345,10 @@ static bool shouldConvertImpl(const Constant *Cst) {
if (Cst->isZeroValue())
return false;

// Globals cannot be or contain scalable vectors.
if (Cst->getType()->isScalableTy())
return false;

if (Stress)
return true;

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20 changes: 20 additions & 0 deletions llvm/test/CodeGen/AArch64/no-promote-scalabale-const-to-global.ll
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@@ -0,0 +1,20 @@
; RUN: llc -mtriple=aarch64 -mattr=+sve -stop-after=aarch64-promote-const < %s | FileCheck %s

; Test that the constant inside the `phi` is not promoted to a global
; CHECK-NOT: _PromotedConst
define void @f(i1 %c, ptr %p, ptr %q) {
entry:
br i1 %c, label %if.then, label %if.else

if.then:
%u = load [2 x <vscale x 4 x float> ], ptr %p
br label %exit

if.else:
br label %exit

exit:
%v = phi [2 x <vscale x 4 x float> ] [ %u, %if.then], [[<vscale x 4 x float> zeroinitializer, <vscale x 4 x float> poison], %if.else]
store [2 x <vscale x 4 x float>] %v, ptr %q
ret void
}