[PATCH] D74322: GlobalISel: Extend narrowing to G_ASHR

[Matt Arsenault via Phabricator via llvm-commits]

arsenm marked an inline comment as done.
arsenm added inline comments.


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Comment at: llvm/lib/CodeGen/GlobalISel/CombinerHelper.cpp:1488
+    if (ShiftVal == HalfSize - 1) {
+      // (G_ASHR i64:x, 32) ->
+      //   G_MERGE_VALUES lo_32(x), (G_ASHR hi_32(x), 31)
----------------
foad wrote:
> "32" should be "31" here, but in any case this whole clause makes no sense to me. Why would shifting a 64-bit value right by 31 leave the low half unchanged?
I broke this when I did a cleanup pass, this should just be HalfSize


CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D74322/new/

https://reviews.llvm.org/D74322