[llvm] [AArch64] Drop flags from BSP pseudos (PR #151856)

[David Green via llvm-commits]

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@@ -96,3 +96,23 @@ body:             |
     $q25 = ORRv16i8 $q3, killed $q3
     RET_ReallyLR implicit $q22
 ...
+---
+name:            DoubleOp
+tracksRegLiveness: true
+body:             |
+  bb.0.entry:
+    liveins: $q2
+
+    ; CHECK-LABEL: name: DoubleOp
+    ; CHECK: liveins: $q2
+    ; CHECK-NEXT: {{  $}}
+    ; CHECK-NEXT: renamable $q0 = MOVIv8i16 1, 0
+    ; CHECK-NEXT: renamable $q1 = ORRv16i8 renamable $q2, renamable $q2
+    ; CHECK-NEXT: renamable $q1 = BSLv16i8 killed renamable $q1, renamable $q2, renamable $q0
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davemgreen wrote:

It is unlikely to be worth it to so long as the kill flags are not incorrect. We should for the most part not expect degenerate cases here, we just have to handle them correctly if they do come up.

https://github.com/llvm/llvm-project/pull/151856