Add -O0 support for @llvm.invariant.group.barrier by discarding it if it gets to ISel.

Differential Revision: https://reviews.llvm.org/D26292

llvm-svn: 286119

3 files changed, 9 insertions, 0 deletions

diff --git a/llvm/lib/CodeGen/SelectionDAG/FastISel.cpp b/llvm/lib/CodeGen/SelectionDAG/FastISel.cpp
index 4ca22497703..452bb059494 100644
--- a/llvm/lib/CodeGen/SelectionDAG/FastISel.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/FastISel.cpp
@@ -1216,6 +1216,7 @@ bool FastISel::selectIntrinsicCall(const IntrinsicInst *II) {
     updateValueMap(II, ResultReg);
     return true;
   }
+  case Intrinsic::invariant_group_barrier:
   case Intrinsic::expect: {
     unsigned ResultReg = getRegForValue(II->getArgOperand(0));
     if (!ResultReg)
diff --git a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
index eea5dcc0cf4..b588d9b193f 100644
--- a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
@@ -5460,6 +5460,7 @@ SelectionDAGBuilder::visitIntrinsicCall(const CallInst &I, unsigned Intrinsic) {
   }
   case Intrinsic::annotation:
   case Intrinsic::ptr_annotation:
+  case Intrinsic::invariant_group_barrier:
     // Drop the intrinsic, but forward the value
     setValue(&I, getValue(I.getOperand(0)));
     return nullptr;
diff --git a/llvm/test/CodeGen/Generic/intrinsics.ll b/llvm/test/CodeGen/Generic/intrinsics.ll
index 29bc499adfc..4d04786a58d 100644
--- a/llvm/test/CodeGen/Generic/intrinsics.ll
+++ b/llvm/test/CodeGen/Generic/intrinsics.ll
@@ -1,4 +1,5 @@
 ; RUN: llc < %s
+; RUN: llc -O0 < %s
 
 ;; SQRT
 declare float @llvm.sqrt.f32(float)
@@ -38,3 +39,9 @@ define double @test_cos(float %F) {
         ret double %I
 }
 
+declare i8* @llvm.invariant.group.barrier(i8*)
+
+define i8* @barrier(i8* %p) {
+        %q = call i8* @llvm.invariant.group.barrier(i8* %p)
+        ret i8* %q
+}