[AMDGPU] Add some missing always-uniform values.

This commit adds some missing intrinsics into the isAlwaysUniform list
for the AMDGPU backend.

Differential Revision: https://reviews.llvm.org/D56845

llvm-svn: 351562

Author: Neil Henning

llvm/lib/Target/AMDGPU/AMDGPUTargetTransformInfo.cpp

@@ -579,6 +579,8 @@ bool GCNTTIImpl::isAlwaysUniform(const Value *V) const {
       return false;
     case Intrinsic::amdgcn_readfirstlane:
     case Intrinsic::amdgcn_readlane:
+    case Intrinsic::amdgcn_icmp:
+    case Intrinsic::amdgcn_fcmp:
       return true;
     }
   }

llvm/test/Analysis/DivergenceAnalysis/AMDGPU/always_uniform.ll

@@ -1,14 +1,32 @@
 ; RUN: opt  -mtriple amdgcn-unknown-amdhsa -analyze -divergence -use-gpu-divergence-analysis %s | FileCheck %s
 
-define amdgpu_kernel void @workitem_id_x() #1 {
+; CHECK: for function 'readfirstlane':
+define amdgpu_kernel void @readfirstlane() {
   %id.x = call i32 @llvm.amdgcn.workitem.id.x()
 ; CHECK: DIVERGENT:  %id.x = call i32 @llvm.amdgcn.workitem.id.x()
   %first.lane = call i32 @llvm.amdgcn.readfirstlane(i32 %id.x)
 ; CHECK-NOT: DIVERGENT:  %first.lane = call i32 @llvm.amdgcn.readfirstlane(i32 %id.x)
   ret void
 }
 
+; CHECK: for function 'icmp':
+define amdgpu_kernel void @icmp(i32 inreg %x) {
+; CHECK-NOT: DIVERGENT:  %icmp = call i64 @llvm.amdgcn.icmp.i32
+  %icmp = call i64 @llvm.amdgcn.icmp.i32(i32 %x, i32 0, i32 33)
+  ret void
+}
+
+; CHECK: for function 'fcmp':
+define amdgpu_kernel void @fcmp(float inreg %x, float inreg %y) {
+; CHECK-NOT: DIVERGENT:  %fcmp = call i64 @llvm.amdgcn.fcmp.i32
+  %fcmp = call i64 @llvm.amdgcn.fcmp.i32(float %x, float %y, i32 33)
+  ret void
+}
+
 declare i32 @llvm.amdgcn.workitem.id.x() #0
 declare i32 @llvm.amdgcn.readfirstlane(i32) #0
+declare i64 @llvm.amdgcn.icmp.i32(i32, i32, i32) #1
+declare i64 @llvm.amdgcn.fcmp.i32(float, float, i32) #1
 
 attributes #0 = { nounwind readnone }
+attributes #1 = { nounwind readnone convergent }