[llvm] [GlobalISel] Combine G_MERGE_VALUES of undef (PR #113381)

[David Green via llvm-commits]

Thorsten =?utf-8?q?Schütt?= <schuett at gmail.com>,
Thorsten =?utf-8?q?Schütt?= <schuett at gmail.com>
Message-ID:
In-Reply-To: <llvm.org/llvm/llvm-project/pull/113381 at github.com>


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@@ -420,7 +420,8 @@ def unary_undef_to_zero: GICombineRule<
 // replaced with undef.
 def propagate_undef_any_op: GICombineRule<
   (defs root:$root),
-  (match (wip_match_opcode G_ADD, G_FPTOSI, G_FPTOUI, G_SUB, G_XOR, G_TRUNC, G_BITCAST, G_ANYEXT):$root,
+  (match (wip_match_opcode G_ADD, G_FPTOSI, G_FPTOUI, G_SUB, G_XOR, G_TRUNC, G_BITCAST,
+                           G_ANYEXT, G_MERGE_VALUES):$root,
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davemgreen wrote:

bswap_i16_to_i128_anyext for example looks like it should end up with something from the input in the top bits, not just zeros.

https://github.com/llvm/llvm-project/pull/113381