[llvm] r238762 - Teach the IR Sink pass to (conservatively) respect convergent annotations.

[Owen Anderson]

Author: resistor
Date: Mon Jun  1 12:20:31 2015
New Revision: 238762

URL: http://llvm.org/viewvc/llvm-project?rev=238762&view=rev
Log:
Teach the IR Sink pass to (conservatively) respect convergent annotations.

Added:
    llvm/trunk/test/Transforms/Sink/convergent.ll
Modified:
    llvm/trunk/lib/Transforms/Scalar/Sink.cpp

Modified: llvm/trunk/lib/Transforms/Scalar/Sink.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Scalar/Sink.cpp?rev=238762&r1=238761&r2=238762&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Scalar/Sink.cpp (original)
+++ llvm/trunk/lib/Transforms/Scalar/Sink.cpp Mon Jun  1 12:20:31 2015
@@ -172,6 +172,12 @@ static bool isSafeToMove(Instruction *In
   if (isa<TerminatorInst>(Inst) || isa<PHINode>(Inst))
     return false;
 
+  // Convergent operations can only be moved to control equivalent blocks.
+  if (auto CS = CallSite(Inst)) {
+    if (CS.hasFnAttr(Attribute::Convergent))
+      return false;
+  }
+
   return true;
 }
 

Added: llvm/trunk/test/Transforms/Sink/convergent.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/Sink/convergent.ll?rev=238762&view=auto
==============================================================================
--- llvm/trunk/test/Transforms/Sink/convergent.ll (added)
+++ llvm/trunk/test/Transforms/Sink/convergent.ll Mon Jun  1 12:20:31 2015
@@ -0,0 +1,24 @@
+; RUN: opt -sink -S < %s | FileCheck %s
+
+; Verify that IR sinking does not move convergent operations to
+; blocks that are not control equivalent.
+
+; CHECK: define i32 @foo
+; CHECK: entry
+; CHECK-NEXT: call i32 @bar
+; CHECK-NEXT: br i1 %arg
+
+define i32 @foo(i1 %arg) {
+entry:
+  %c = call i32 @bar() readonly convergent
+  br i1 %arg, label %then, label %end
+
+then:
+  ret i32 %c
+
+end:
+  ret i32 0
+}
+
+declare i32 @bar() readonly convergent
+