SimplifyCFG has a heuristics for out-of-order processors that decides when it is...

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@194346 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Transforms/Utils/SimplifyCFG.cpp b/lib/Transforms/Utils/SimplifyCFG.cpp
index 1398697dc55737082e1011489b5e9f99c7f0013a..d36d9dc1b96e056c196ec0a28e7f5b7c377ccd3f 100644 (file)
--- a/lib/Transforms/Utils/SimplifyCFG.cpp
+++ b/lib/Transforms/Utils/SimplifyCFG.cpp
@@ -2096,7 +2096,7 @@ bool llvm::FoldBranchToCommonDest(BranchInst *BI) {
       for (Instruction::op_iterator OI = BonusInst->op_begin(),
            OE = BonusInst->op_end(); OI != OE; ++OI) {
         Value *V = *OI;
-        if (!isa<Constant>(V))
+        if (!isa<Constant>(V) && !isa<Argument>(V))
           UsedValues.insert(V);
       }
 

diff --git a/test/Transforms/SimplifyCFG/common-dest-folding.ll b/test/Transforms/SimplifyCFG/common-dest-folding.ll
new file mode 100644 (file)
index 0000000..10fb7d4
--- /dev/null
+++ b/test/Transforms/SimplifyCFG/common-dest-folding.ll
@@ -0,0 +1,28 @@
+; RUN: opt < %s -simplifycfg -S | FileCheck %s
+
+;CHECK: @foo
+;CHECK: and i32 %c1, %k
+;CHECK: icmp eq i32
+;CHECK: and i32 %c2, %k
+;CHECK: icmp eq i32
+;CHECK: or i1
+;CHECK: ret
+define i32 @foo(i32 %k, i32 %c1, i32 %c2) {
+  %1 = and i32 %c1, %k
+  %2 = icmp eq i32 %1, 0
+  br i1 %2, label %8, label %3
+
+; <label>:3                                       ; preds = %0
+  %4 = and i32 %c2, %k
+  %5 = icmp eq i32 %4, 0
+  br i1 %5, label %8, label %6
+
+; <label>:6                                       ; preds = %3
+  %7 = tail call i32 (...)* @bar() nounwind
+  br label %8
+
+; <label>:8                                       ; preds = %3, %0, %6
+  ret i32 undef
+}
+
+declare i32 @bar(...)