[llvm] [InstCombine] Pull unary shuffles through fneg/fabs (PR #144933)

[Luke Lau via llvm-commits]

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@@ -205,9 +205,10 @@ define <4 x double> @matrix_multiply_two_operands_negated_with_same_size(<2 x do
 
 define <2 x double> @matrix_multiply_two_operands_with_multiple_uses(<6 x double> %a, <3 x double> %b) {
 ; CHECK-LABEL: @matrix_multiply_two_operands_with_multiple_uses(
-; CHECK-NEXT:    [[RES:%.*]] = tail call <2 x double> @llvm.matrix.multiply.v2f64.v6f64.v3f64(<6 x double> [[A:%.*]], <3 x double> [[B:%.*]], i32 2, i32 3, i32 1)
-; CHECK-NEXT:    [[TMP1:%.*]] = shufflevector <6 x double> [[A]], <6 x double> poison, <2 x i32> <i32 0, i32 1>
-; CHECK-NEXT:    [[RES_3:%.*]] = fsub <2 x double> [[RES]], [[TMP1]]
+; CHECK-NEXT:    [[A_NEG:%.*]] = fneg <6 x double> [[A:%.*]]
+; CHECK-NEXT:    [[RES:%.*]] = tail call <2 x double> @llvm.matrix.multiply.v2f64.v6f64.v3f64(<6 x double> [[A]], <3 x double> [[B:%.*]], i32 2, i32 3, i32 1)
+; CHECK-NEXT:    [[RES_2:%.*]] = shufflevector <6 x double> [[A_NEG]], <6 x double> poison, <2 x i32> <i32 0, i32 1>
+; CHECK-NEXT:    [[RES_3:%.*]] = fadd <2 x double> [[RES_2]], [[RES]]
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lukel97 wrote:

I don't really have a good answer for this diff other than that it still seems to test what its supposed to test, i.e. that the operands to the intrinsic get swapped out with their non-negative counterparts.

https://github.com/llvm/llvm-project/pull/144933