ifcvt should ignore cfg where true and false successors are the same.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@73423 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/IfConversion.cpp b/lib/CodeGen/IfConversion.cpp
index 1d0887f..4d5c3c2 100644
--- a/lib/CodeGen/IfConversion.cpp
+++ b/lib/CodeGen/IfConversion.cpp
@@ -547,7 +547,11 @@
// fallthrough.
if (!BBI.FalseBB)
BBI.FalseBB = findFalseBlock(BBI.BB, BBI.TrueBB);
- assert(BBI.FalseBB && "Expected to find the fallthrough block!");
+ if (!BBI.FalseBB) {
+ // Malformed bcc? True and false blocks are the same?
+ BBI.IsUnpredicable = true;
+ return;
+ }
}
// Then scan all the instructions.
@@ -663,6 +667,13 @@
return BBI;
}
+ // Do not ifcvt if true and false fallthrough blocks are the same.
+ if (!BBI.FalseBB) {
+ BBI.IsBeingAnalyzed = false;
+ BBI.IsAnalyzed = true;
+ return BBI;
+ }
+
BBInfo &TrueBBI = AnalyzeBlock(BBI.TrueBB, Tokens);
BBInfo &FalseBBI = AnalyzeBlock(BBI.FalseBB, Tokens);
diff --git a/test/CodeGen/ARM/ifcvt9.ll b/test/CodeGen/ARM/ifcvt9.ll
new file mode 100644
index 0000000..bbd2f2e
--- /dev/null
+++ b/test/CodeGen/ARM/ifcvt9.ll
@@ -0,0 +1,12 @@
+; RUN: llvm-as < %s | llc -march=arm
+
+define fastcc void @t() nounwind {
+entry:
+ br i1 undef, label %bb.i.i3, label %growMapping.exit
+
+bb.i.i3: ; preds = %entry
+ unreachable
+
+growMapping.exit: ; preds = %entry
+ unreachable
+}