[llvm] 36272d5 - Let isGuaranteedNotToBeUndefOrPoison consider PHINode with constant values

[Juneyoung Lee via llvm-commits]

Author: Juneyoung Lee
Date: 2020-02-04T16:46:54+09:00
New Revision: 36272d5f005f85ffa20eb57544865c3da584c4ce

URL: https://github.com/llvm/llvm-project/commit/36272d5f005f85ffa20eb57544865c3da584c4ce
DIFF: https://github.com/llvm/llvm-project/commit/36272d5f005f85ffa20eb57544865c3da584c4ce.diff

LOG: Let isGuaranteedNotToBeUndefOrPoison consider PHINode with constant values

Added: 
    

Modified: 
    llvm/lib/Analysis/ValueTracking.cpp

Removed: 
    


################################################################################
diff  --git a/llvm/lib/Analysis/ValueTracking.cpp b/llvm/lib/Analysis/ValueTracking.cpp
index a6bb2bc9d6cf..6b88cd05b2d7 100644
--- a/llvm/lib/Analysis/ValueTracking.cpp
+++ b/llvm/lib/Analysis/ValueTracking.cpp
@@ -4522,6 +4522,13 @@ bool llvm::isGuaranteedNotToBeUndefOrPoison(const Value *V) {
   if (isa<ConstantInt>(V) || isa<GlobalVariable>(V))
     return true;
 
+  if (auto PN = dyn_cast<PHINode>(V)) {
+    if (llvm::all_of(PN->incoming_values(), [](const Use &U) {
+          return isa<ConstantInt>(U.get());
+        }))
+      return true;
+  }
+
   return false;
 }