[llvm] Remove the optional bitcast between a musttail call and its ret (PR #201280)

[Arseniy Obolenskiy via llvm-commits]

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@@ -0,0 +1,20 @@
+; RUN: llvm-dis %s.bc -o - | FileCheck %s
+; RUN: verify-uselistorder %s.bc
+
+; musttail-bitcast-upgrade.ll.bc was produced from the IR below using an
+; llvm-as that still emitted the optional no-op bitcast between a musttail call
+; and its return. The reader must drop that bitcast so the module verifies.
+
+; CHECK-LABEL: define ptr @caller(ptr %a)
+; CHECK-NEXT:    %c = musttail call ptr @callee(ptr %a)
+; CHECK-NEXT:    ret ptr %c
+
+define ptr @callee(ptr %a) {
+  ret ptr %a
+}
+
+define ptr @caller(ptr %a) {
+  %c = musttail call ptr @callee(ptr %a)
+  %b = bitcast ptr %c to ptr
+  ret ptr %b
+}
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aobolensk wrote:

Done

https://github.com/llvm/llvm-project/pull/201280