[llvm] 058a223 - [HLSL] Add wave active ballot to set of wave ops that set waveops shader flag (#177043)

[via llvm-commits]

Author: Joshua Batista
Date: 2026-01-21T10:06:04-08:00
New Revision: 058a223388576cc7f037f8155967a73d5400b053

URL: https://github.com/llvm/llvm-project/commit/058a223388576cc7f037f8155967a73d5400b053
DIFF: https://github.com/llvm/llvm-project/commit/058a223388576cc7f037f8155967a73d5400b053.diff

LOG: [HLSL] Add wave active ballot to set of wave ops that set waveops shader flag (#177043)

This PR simply adds wave active ballot to the set of wave ops that
switch on the waveops shader flag.

Added: 
    

Modified: 
    llvm/lib/Target/DirectX/DXILShaderFlags.cpp
    llvm/test/CodeGen/DirectX/ShaderFlags/wave-ops.ll

Removed: 
    


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diff  --git a/llvm/lib/Target/DirectX/DXILShaderFlags.cpp b/llvm/lib/Target/DirectX/DXILShaderFlags.cpp
index a4320209c53d6..899f5a666e6d1 100644
--- a/llvm/lib/Target/DirectX/DXILShaderFlags.cpp
+++ b/llvm/lib/Target/DirectX/DXILShaderFlags.cpp
@@ -65,7 +65,6 @@ static bool checkWaveOps(Intrinsic::ID IID) {
   // Currently unsupported intrinsics
   // case Intrinsic::dx_wave_getlanecount:
   // case Intrinsic::dx_wave_allequal:
-  // case Intrinsic::dx_wave_ballot:
   // case Intrinsic::dx_wave_readfirst:
   // case Intrinsic::dx_wave_reduce.and:
   // case Intrinsic::dx_wave_reduce.or:
@@ -89,6 +88,7 @@ static bool checkWaveOps(Intrinsic::ID IID) {
   case Intrinsic::dx_wave_all:
   case Intrinsic::dx_wave_readlane:
   case Intrinsic::dx_wave_active_countbits:
+  case Intrinsic::dx_wave_ballot:
   // Wave Active Op Variants
   case Intrinsic::dx_wave_reduce_sum:
   case Intrinsic::dx_wave_reduce_usum:

diff  --git a/llvm/test/CodeGen/DirectX/ShaderFlags/wave-ops.ll b/llvm/test/CodeGen/DirectX/ShaderFlags/wave-ops.ll
index 3544017062e8e..4b1c1a338b8c7 100644
--- a/llvm/test/CodeGen/DirectX/ShaderFlags/wave-ops.ll
+++ b/llvm/test/CodeGen/DirectX/ShaderFlags/wave-ops.ll
@@ -9,6 +9,7 @@
 ; CHECK-NEXT: ; Note: extra DXIL module flags:
 
 target triple = "dxil-pc-shadermodel6.7-library"
+%dx.types.fouri32 = type { i32, i32, i32, i32 }
 
 ; Test the indiviual ops that they have the same Shader Wave flag at the
 ; function level to ensure that each op is setting it accordingly
@@ -96,3 +97,10 @@ entry:
   %0 = call i32 @llvm.dx.wave.active.countbits(i1 %expr)
   ret void
 }
+
+define void @wave_active_ballot(i1 %expr) {
+entry:
+  ; CHECK: Function wave_active_ballot : [[WAVE_FLAG]]
+  %0 = call %dx.types.fouri32 @llvm.dx.wave.ballot(i1 %expr)
+  ret void
+}