[llvm-branch-commits] [llvm] IR: Stop requiring nsz to reassociate fmul (PR #171726)

[Andy Kaylor via llvm-branch-commits]

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@@ -525,8 +525,7 @@ define <2 x float> @div_constant_dividend2_reassoc_only(<2 x float> %x) {
 
 define <2 x float> @div_constant_dividend3(<2 x float> %x) {
 ; CHECK-LABEL: @div_constant_dividend3(
-; CHECK-NEXT:    [[TMP1:%.*]] = fmul reassoc arcp <2 x float> [[X:%.*]], <float 1.500000e+01, float -7.000000e+00>
-; CHECK-NEXT:    [[T2:%.*]] = fmul reassoc arcp <2 x float> [[TMP1]], <float 0x3FD5555560000000, float 0x3FC24924A0000000>
+; CHECK-NEXT:    [[T2:%.*]] = fmul reassoc arcp <2 x float> [[X:%.*]], <float 5.000000e+00, float -1.000000e+00>
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andykaylor wrote:

This one doesn't look right, but not because of the change in this PR. Shouldn't we have required 1reassoc` and `rcp` on both `fdiv` instructions before converting them into two `fmul` instructions with `ressoc` and `arcp` on both?

https://github.com/llvm/llvm-project/pull/171726