review comments:

  - add constrainAllUses to first spirv op
  - update testcase for ease of reading
  - use enum instead of int equivalent for documentation

Author: inbelic

clang/test/CodeGenHLSL/builtins/WaveActiveCountBits.hlsl

@@ -1,22 +1,18 @@
 // RUN: %clang_cc1 -std=hlsl2021 -finclude-default-header -triple \
 // RUN:   dxil-pc-shadermodel6.3-compute %s -emit-llvm -disable-llvm-passes -o - | \
-// RUN:   FileCheck %s --check-prefixes=CHECK,CHECK-DXIL
+// RUN:   FileCheck %s -DTARGET=dx
 // RUN: %clang_cc1 -std=hlsl2021 -finclude-default-header -triple \
 // RUN:   spirv-pc-vulkan-compute %s -emit-llvm -disable-llvm-passes -o - | \
-// RUN:   FileCheck %s --check-prefixes=CHECK,CHECK-SPIRV
+// RUN:   FileCheck %s -DTARGET=spv
 
 // Test basic lowering to runtime function call.
 
 // CHECK-LABEL: test_bool
 int test_bool(bool expr) {
-  // CHECK-SPIRV: %[[#entry_tok:]] = call token @llvm.experimental.convergence.entry()
-  // CHECK-SPIRV:  %[[RET:.*]] = call spir_func i32 @llvm.spv.wave.active.countbits(i1 %{{.*}}) [ "convergencectrl"(token %[[#entry_tok]]) ]
-  // CHECK-DXIL:  %[[RET:.*]] = call i32 @llvm.dx.wave.active.countbits(i1 %{{.*}})
-  // CHECK:  ret i32 %[[RET]]
+  // CHECK:  call {{.*}} @llvm.[[TARGET]].wave.active.countbits
   return WaveActiveCountBits(expr);
 }
 
-// CHECK-DXIL: declare i32 @llvm.dx.wave.active.countbits(i1) #[[#attr:]]
-// CHECK-SPIRV: declare i32 @llvm.spv.wave.active.countbits(i1) #[[#attr:]]
+// CHECK: declare i32 @llvm.[[TARGET]].wave.active.countbits(i1) #[[#attr:]]
 
 // CHECK: attributes #[[#attr]] = {{{.*}} convergent {{.*}}}

llvm/lib/Target/SPIRV/SPIRVInstructionSelector.cpp

@@ -1935,15 +1935,16 @@ bool SPIRVInstructionSelector::selectWaveActiveCountBits(
           .addDef(BallotReg)
           .addUse(GR.getSPIRVTypeID(BallotType))
           .addUse(GR.getOrCreateConstInt(SPIRV::Scope::Subgroup, I, IntTy, TII))
-          .addUse(I.getOperand(2).getReg());
+          .addUse(I.getOperand(2).getReg())
+          .constrainAllUses(TII, TRI, RBI);
 
   Result |=
       BuildMI(BB, I, I.getDebugLoc(),
               TII.get(SPIRV::OpGroupNonUniformBallotBitCount))
           .addDef(ResVReg)
           .addUse(GR.getSPIRVTypeID(ResType))
           .addUse(GR.getOrCreateConstInt(SPIRV::Scope::Subgroup, I, IntTy, TII))
-          .addImm(0)
+          .addImm(SPIRV::GroupOperation::Reduce)
           .addUse(BallotReg)
           .constrainAllUses(TII, TRI, RBI);