[llvm] [ValueTracking] use KnownBits to compute fpclass from bitcast (PR #97762)

[Alex MacLean via llvm-commits]

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@@ -2690,6 +2690,110 @@ entry:
   ret double %abs
 }
 
+define float @bitcast_to_float_sign_0(i32 %arg) {
+; CHECK: Function Attrs: mustprogress nofree norecurse nosync nounwind willreturn memory(none)
+; CHECK-LABEL: define nofpclass(ninf nzero nsub nnorm) float @bitcast_to_float_sign_0
+; CHECK-SAME: (i32 [[ARG:%.*]]) #[[ATTR3]] {
+; CHECK-NEXT:    [[TMP1:%.*]] = lshr i32 [[ARG]], 1
+; CHECK-NEXT:    [[TMP2:%.*]] = bitcast i32 [[TMP1]] to float
+; CHECK-NEXT:    ret float [[TMP2]]
+;
+  %1 = lshr i32 %arg, 1
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AlexMaclean wrote:

Fixed.

https://github.com/llvm/llvm-project/pull/97762