[ConstProp] add IR tests to show miscompiles; NFC

A fix for these is proposed in D51216.

llvm-svn: 353992

Author: rotateright

llvm/test/Transforms/ConstProp/bitcast.ll

@@ -22,3 +22,39 @@ define i1 @bad_icmp_constexpr_bitcast() {
   %cmp = icmp eq i32 ptrtoint (i16* @a to i32), bitcast (float fadd (float bitcast (i32 ptrtoint (i16* @b to i32) to float), float 2.0) to i32)
   ret i1 %cmp
 }
+
+; FIXME: If the bitcasts result in a NaN FP value, then "ordered and equal" would be false.
+
+define i1 @fcmp_constexpr_oeq(float %conv) {
+; CHECK-LABEL: @fcmp_constexpr_oeq(
+; CHECK-NEXT:    ret i1 true
+;
+  %cmp = fcmp oeq float bitcast (i32 ptrtoint (i16* @a to i32) to float), bitcast (i32 ptrtoint (i16* @a to i32) to float)
+  ret i1 %cmp
+}
+
+; FIXME: If the bitcasts result in a NaN FP value, then "unordered or not equal" would be true.
+
+define i1 @fcmp_constexpr_une(float %conv) {
+; CHECK-LABEL: @fcmp_constexpr_une(
+; CHECK-NEXT:    ret i1 false
+;
+  %cmp = fcmp une float bitcast (i32 ptrtoint (i16* @a to i32) to float), bitcast (i32 ptrtoint (i16* @a to i32) to float)
+  ret i1 %cmp
+}
+
+define i1 @fcmp_constexpr_ueq(float %conv) {
+; CHECK-LABEL: @fcmp_constexpr_ueq(
+; CHECK-NEXT:    ret i1 true
+;
+  %cmp = fcmp ueq float bitcast (i32 ptrtoint (i16* @a to i32) to float), bitcast (i32 ptrtoint (i16* @a to i32) to float)
+  ret i1 %cmp
+}
+
+define i1 @fcmp_constexpr_one(float %conv) {
+; CHECK-LABEL: @fcmp_constexpr_one(
+; CHECK-NEXT:    ret i1 false
+;
+  %cmp = fcmp one float bitcast (i32 ptrtoint (i16* @a to i32) to float), bitcast (i32 ptrtoint (i16* @a to i32) to float)
+  ret i1 %cmp
+}