ValueToValueMapTy VMap;
BasicBlock *DirectSucc = CloneBasicBlock(Target, VMap, ".clone", &F);
- for (BasicBlock *Pred : OtherPreds)
- Pred->getTerminator()->replaceUsesOfWith(Target, DirectSucc);
+ for (BasicBlock *Pred : OtherPreds) {
+ // If the target is a loop to itself, then the terminator of the split
+ // block needs to be updated.
+ if (Pred == Target)
+ BodyBlock->getTerminator()->replaceUsesOfWith(Target, DirectSucc);
+ else
+ Pred->getTerminator()->replaceUsesOfWith(Target, DirectSucc);
+ }
// Ok, now fix up the PHIs. We know the two blocks only have PHIs, and that
// they are clones, so the number of PHIs are the same.
--- /dev/null
+; RUN: opt -codegenprepare -S < %s | FileCheck %s
+
+; Test that an invalid CFG is not created by splitIndirectCriticalEdges
+; transformation when the 'target' block is a loop to itself.
+
+; CHECK: .split:
+; CHECK: br label %while.body.clone
+; CHECK: if.else1:
+; CHECK: indirectbr
+; CHECK: while.body.clone:
+; CHECK: br label %.split
+
+define void @test() {
+entry:
+ br label %if.else
+
+if.else:
+ br i1 undef, label %while.body, label %preheader
+
+preheader:
+ br label %if.else1
+
+if.then:
+ unreachable
+
+while.body:
+ %dest.sroa = phi i32 [ %1, %while.body ], [ undef, %if.else1 ], [ undef, %if.else ]
+ %0 = inttoptr i32 %dest.sroa to i8*
+ %incdec.ptr = getelementptr inbounds i8, i8* %0, i32 -1
+ %1 = ptrtoint i8* %incdec.ptr to i32
+ store i8 undef, i8* %incdec.ptr, align 1
+ br label %while.body
+
+if.else1:
+ indirectbr i8* undef, [label %if.then, label %while.body, label %if.else, label %if.else1]
+}
+