[llvm] [AArch64][GlobalISel] Combine MUL(AND(LSHR(X, 15), 0x10001), 0xffff) to CMLTz (PR #92915)

[via llvm-commits]

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@@ -1,11 +1,22 @@
 ; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
-; RUN: llc -mtriple=aarch64 %s -o - | FileCheck %s
+; RUN: llc -mtriple=aarch64 %s -o - | FileCheck %s --check-prefixes=CHECK,CHECK-SD
+; RUN: llc -mtriple=aarch64 %s -o - -global-isel -global-isel-abort=2 2>&1 | FileCheck %s --check-prefixes=CHECK,CHECK-GI
 
 define <1 x i64> @v1i64(<1 x i64> %a) {
-; CHECK-LABEL: v1i64:
-; CHECK:       // %bb.0:
-; CHECK-NEXT:    cmlt v0.2s, v0.2s, #0
-; CHECK-NEXT:    ret
+; CHECK-SD-LABEL: v1i64:
+; CHECK-SD:       // %bb.0:
+; CHECK-SD-NEXT:    cmlt v0.2s, v0.2s, #0
+; CHECK-SD-NEXT:    ret
+;
+; CHECK-GI-LABEL: v1i64:
+; CHECK-GI:       // %bb.0:
+; CHECK-GI-NEXT:    fmov x8, d0
+; CHECK-GI-NEXT:    lsr x8, x8, #31
+; CHECK-GI-NEXT:    and x8, x8, #0x100000001
+; CHECK-GI-NEXT:    lsl x9, x8, #32
+; CHECK-GI-NEXT:    sub x8, x9, x8
+; CHECK-GI-NEXT:    fmov d0, x8
+; CHECK-GI-NEXT:    ret
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chuongg3 wrote:

In GlobalISel, all v1 types are treated as scalar values and we do not necessarily want the same optimization for scalar types.

https://github.com/llvm/llvm-project/pull/92915