[llvm] [GlobalISel] Combine G_MERGE_VALUES of x and undef (PR #113616)

[Amara Emerson via llvm-commits]

Thorsten =?utf-8?q?Sch=C3=BCtt?= <schuett at gmail.com>,
Thorsten =?utf-8?q?Sch=C3=BCtt?= <schuett at gmail.com>,
Thorsten =?utf-8?q?Sch=C3=BCtt?= <schuett at gmail.com>
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In-Reply-To: <llvm.org/llvm/llvm-project/pull/113616 at github.com>


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@@ -1440,6 +1440,7 @@ define i65 @v_sext_inreg_i65_22(i65 %value) {
 ; GFX6-LABEL: v_sext_inreg_i65_22:
 ; GFX6:       ; %bb.0:
 ; GFX6-NEXT:    s_waitcnt vmcnt(0) expcnt(0) lgkmcnt(0)
+; GFX6-NEXT:    v_mov_b32_e32 v3, 0
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aemerson wrote:

These are regressions precisely because you're over-defining the MIR.

https://github.com/llvm/llvm-project/pull/113616