[llvm] r244348 - [ConstantFoldTerminator] Preserve make.implicit metadata when converting SwitchInst to BranchInst

[Chen Li via llvm-commits]

Author: chenli
Date: Fri Aug  7 14:30:12 2015
New Revision: 244348

URL: http://llvm.org/viewvc/llvm-project?rev=244348&view=rev
Log:
[ConstantFoldTerminator] Preserve make.implicit metadata when converting SwitchInst to BranchInst

Summary: llvm::ConstantFoldTerminator function can convert SwitchInst with single case (and default) to a conditional BranchInst. This patch adds support to preserve make.implicit metadata on this conversion.

Reviewers: sanjoy, weimingz, chenli

Subscribers: mcrosier, llvm-commits

Differential Revision: http://reviews.llvm.org/D11841

Added:
    llvm/trunk/test/Transforms/SimplifyCFG/preserve-make-implicit-on-switch-to-br.ll
Modified:
    llvm/trunk/lib/Transforms/Utils/Local.cpp

Modified: llvm/trunk/lib/Transforms/Utils/Local.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Utils/Local.cpp?rev=244348&r1=244347&r2=244348&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Utils/Local.cpp (original)
+++ llvm/trunk/lib/Transforms/Utils/Local.cpp Fri Aug  7 14:30:12 2015
@@ -229,6 +229,11 @@ bool llvm::ConstantFoldTerminator(BasicB
                                             SIDef->getValue().getZExtValue()));
       }
 
+      // Update make.implicit metadata to the newly-created conditional branch.
+      MDNode *MakeImplicitMD = SI->getMetadata(LLVMContext::MD_make_implicit);
+      if (MakeImplicitMD)
+        NewBr->setMetadata(LLVMContext::MD_make_implicit, MakeImplicitMD);
+
       // Delete the old switch.
       SI->eraseFromParent();
       return true;

Added: llvm/trunk/test/Transforms/SimplifyCFG/preserve-make-implicit-on-switch-to-br.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/SimplifyCFG/preserve-make-implicit-on-switch-to-br.ll?rev=244348&view=auto
==============================================================================
--- llvm/trunk/test/Transforms/SimplifyCFG/preserve-make-implicit-on-switch-to-br.ll (added)
+++ llvm/trunk/test/Transforms/SimplifyCFG/preserve-make-implicit-on-switch-to-br.ll Fri Aug  7 14:30:12 2015
@@ -0,0 +1,30 @@
+; RUN: opt %s -simplifycfg -S | FileCheck %s
+
+; ConstantFoldTerminator function can convert SwitchInst with one case (and default) to
+; a conditional BranchInst. This test checks the converted BranchInst preserve the 
+; make.implicit metadata.
+
+declare i32 @consume(i32*)
+declare void @trap()
+
+define i32 @copy-metadata(i32* %x) {
+
+entry:
+  %x.int = ptrtoint i32* %x to i64
+  
+; CHECK: br i1 %cond, label %is_null, label %default, !make.implicit !0
+  switch i64 %x.int, label %default [
+    i64 0, label %is_null
+  ], !make.implicit !0
+  
+default:
+  %0 = call i32 @consume(i32* %x)
+  ret i32 %0
+
+is_null:
+  call void @trap()
+  unreachable
+}
+
+!0 = !{}
+