[llvm] [RegisterCoalescer] The COPY with the implicit-def of super register is not coalescable. (PR #169997)

[Sander de Smalen via llvm-commits]

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@@ -0,0 +1,19 @@
+; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py UTC_ARGS: --version 6
+; RUN: llc < %s -mtriple=x86_64-unknown-linux-gnu | FileCheck %s
+
+; FIXME: The first instruction should be `movl %edi, %eax`.
+
+define i64 @fn1(i64 %arg, ptr %arg1) {
+; CHECK-LABEL: fn1:
+; CHECK:       # %bb.0:
+; CHECK-NEXT:    movq %rdi, %rax
+; CHECK-NEXT:    movb (%rsi), %al
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sdesmalen-arm wrote:

For this PR in isolation, with and without your code change, the result seems the same?

https://github.com/llvm/llvm-project/pull/169997