[llvm] [PromoteMemToReg] Insert store undef when removing lifetime markers (PR #191909)

[Orlando Cazalet-Hyams via llvm-commits]

================
@@ -21,8 +21,8 @@
 ; CHECK: %call = call
 ; CHECK-NEXT: %0 = extractvalue { <2 x float>, <2 x float> } %call, 0
 ; CHECK-NEXT: %1 = extractvalue { <2 x float>, <2 x float> } %call, 1
-; CHECK-NEXT: #dbg_value(<2 x float> %0, ![[var:[0-9]+]], !DIExpression(DW_OP_LLVM_fragment, 256, 64),
-; CHECK-NEXT: #dbg_value(<2 x float> %1, ![[var]], !DIExpression(DW_OP_LLVM_fragment, 320, 64),
+; CHECK-NEXT: #dbg_value(<2 x float> undef, ![[var:[0-9]+]], !DIExpression(DW_OP_LLVM_fragment, 256, 64),
+; CHECK-NEXT: #dbg_value(<2 x float> undef, ![[var]], !DIExpression(DW_OP_LLVM_fragment, 320, 64),
----------------
OCHyams wrote:

+1 I agree this looks like a debug info regression, and if it's not it needs to be understood and explained please. Happy to help if you've got any questions

https://github.com/llvm/llvm-project/pull/191909