[llvm] InstCombine: Handle canonicalize in SimplifyDemandedFPClass (PR #173189)

[Matt Arsenault via llvm-commits]

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@@ -323,9 +313,7 @@ define nofpclass(nan) float @ret_nofpclass_nan__canonicalize_select_unknown_or_s
 ; CHECK-LABEL: define nofpclass(nan) float @ret_nofpclass_nan__canonicalize_select_unknown_or_snan(
 ; CHECK-SAME: float [[X:%.*]], i1 [[COND:%.*]]) {
 ; CHECK-NEXT:    [[SNAN:%.*]] = call float @returns_snan()
-; CHECK-NEXT:    [[SELECT:%.*]] = select i1 [[COND]], float [[X]], float [[SNAN]]
-; CHECK-NEXT:    [[CANON:%.*]] = call float @llvm.canonicalize.f32(float [[SELECT]])
-; CHECK-NEXT:    ret float [[CANON]]
+; CHECK-NEXT:    ret float [[X]]
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arsenm wrote:

No, the snan case is not returned since that would be poison. It returns the only possible non-poison result 

https://github.com/llvm/llvm-project/pull/173189