1 files changed, 41 insertions, 3 deletions
diff --git a/llvm/lib/CodeGen/CodeGenPrepare.cpp b/llvm/lib/CodeGen/CodeGenPrepare.cpp
index 49836254356..641316105c0 100644
--- a/llvm/lib/CodeGen/CodeGenPrepare.cpp
+++ b/llvm/lib/CodeGen/CodeGenPrepare.cpp
@@ -600,13 +600,51 @@ simplifyRelocatesOffABase(IntrinsicInst *RelocatedBase,
     // Create a Builder and replace the target callsite with a gep
     IRBuilder<> Builder(ToReplace);
     Builder.SetCurrentDebugLocation(ToReplace->getDebugLoc());
+
+    // If gc_relocate does not match the actual type, cast it to the right type.
+    // In theory, there must be a bitcast after gc_relocate if the type does not
+    // match, and we should reuse it to get the derived pointer. But it could be
+    // cases like this:
+    // bb1:
+    //  ...
+    //  %g1 = call coldcc i8 addrspace(1)* @llvm.experimental.gc.relocate.p1i8(...)
+    //  br label %merge
+    //
+    // bb2:
+    //  ...
+    //  %g2 = call coldcc i8 addrspace(1)* @llvm.experimental.gc.relocate.p1i8(...)
+    //  br label %merge
+    //
+    // merge:
+    //  %p1 = phi i8 addrspace(1)* [ %g1, %bb1 ], [ %g2, %bb2 ]
+    //  %cast = bitcast i8 addrspace(1)* %p1 in to i32 addrspace(1)*
+    //
+    // In this case, we can not find the bitcast any more. So we insert a new bitcast
+    // no matter there is already one or not. In this way, we can handle all cases, and
+    // the extra bitcast should be optimized away in later passes.
+    Instruction *ActualRelocatedBase = RelocatedBase;
+    if (RelocatedBase->getType() != Base->getType()) {
+      ActualRelocatedBase =
+          cast<Instruction>(Builder.CreateBitCast(RelocatedBase, Base->getType()));
+      ActualRelocatedBase->removeFromParent();
+      ActualRelocatedBase->insertAfter(cast<Instruction>(RelocatedBase));
+    }
     Value *Replacement = Builder.CreateGEP(
-        Derived->getSourceElementType(), RelocatedBase, makeArrayRef(OffsetV));
+        Derived->getSourceElementType(), ActualRelocatedBase, makeArrayRef(OffsetV));
     Instruction *ReplacementInst = cast<Instruction>(Replacement);
     ReplacementInst->removeFromParent();
-    ReplacementInst->insertAfter(RelocatedBase);
+    ReplacementInst->insertAfter(ActualRelocatedBase);
     Replacement->takeName(ToReplace);
-    ToReplace->replaceAllUsesWith(Replacement);
+    // If the newly generated derived pointer's type does not match the original derived
+    // pointer's type, cast the new derived pointer to match it. Same reasoning as above.
+    Instruction *ActualReplacement = ReplacementInst;
+    if (ReplacementInst->getType() != ToReplace->getType()) {
+      ActualReplacement =
+          cast<Instruction>(Builder.CreateBitCast(ReplacementInst, ToReplace->getType()));
+      ActualReplacement->removeFromParent();
+      ActualReplacement->insertAfter(ReplacementInst);
+    }
+    ToReplace->replaceAllUsesWith(ActualReplacement);
     ToReplace->eraseFromParent();
 
     MadeChange = true;