[llvm] [GISel] funnel shift combiner port from SelectionDAG ISel to GlobalISel (PR #135132)

[Axel Sorenson via llvm-commits]

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@@ -674,14 +674,12 @@ define i32 @or_shl_fshl_simplify(i32 %x, i32 %y, i32 %s) {
 ; CHECK-GI-LABEL: or_shl_fshl_simplify:
 ; CHECK-GI:       // %bb.0:
 ; CHECK-GI-NEXT:    mov w8, #31 // =0x1f
-; CHECK-GI-NEXT:    and w9, w2, #0x1f
-; CHECK-GI-NEXT:    lsr w10, w0, #1
-; CHECK-GI-NEXT:    lsl w11, w1, w2
+; CHECK-GI-NEXT:    lsr w9, w0, #1
+; CHECK-GI-NEXT:    and w10, w2, #0x1f
 ; CHECK-GI-NEXT:    bic w8, w8, w2
-; CHECK-GI-NEXT:    lsl w9, w1, w9
-; CHECK-GI-NEXT:    lsr w8, w10, w8
-; CHECK-GI-NEXT:    orr w9, w9, w11
-; CHECK-GI-NEXT:    orr w0, w9, w8
+; CHECK-GI-NEXT:    lsl w10, w1, w10
+; CHECK-GI-NEXT:    lsr w8, w9, w8
+; CHECK-GI-NEXT:    orr w0, w10, w8
 ; CHECK-GI-NEXT:    ret
   %shy = shl i32 %y, %s
   %fun = call i32 @llvm.fshl.i32(i32 %y, i32 %x, i32 %s)
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axelcool1234 wrote:

> An Or should be fine with commuted operands.

I just realized this is what you were referring to. I've personally confirmed it does seem to be due to the OR statement at least. I'm not sure why this is happening...

https://github.com/llvm/llvm-project/pull/135132