IntegerType *IntTy = cast<IntegerType>(LHSI->getOperand(0)->getType());
- // Check to see that the input is converted from an integer type that is small
- // enough that preserves all bits. TODO: check here for "known" sign bits.
- // This would allow us to handle (fptosi (x >>s 62) to float) if x is i64 f.e.
- unsigned InputSize = IntTy->getScalarSizeInBits();
-
- // If this is a uitofp instruction, we need an extra bit to hold the sign.
bool LHSUnsigned = isa<UIToFPInst>(LHSI);
- if (LHSUnsigned)
- ++InputSize;
if (I.isEquality()) {
FCmpInst::Predicate P = I.getPredicate();
// equality compares as integer?
}
- // Comparisons with zero are a special case where we know we won't lose
- // information.
- bool IsCmpZero = RHS.isPosZero();
+ // Check to see that the input is converted from an integer type that is small
+ // enough that preserves all bits. TODO: check here for "known" sign bits.
+ // This would allow us to handle (fptosi (x >>s 62) to float) if x is i64 f.e.
+ unsigned InputSize = IntTy->getScalarSizeInBits();
- // If the conversion would lose info, don't hack on this.
- if ((int)InputSize > MantissaWidth && !IsCmpZero)
- return nullptr;
+ // Following test does NOT adjust InputSize downwards for signed inputs,
+ // because the most negative value still requires all the mantissa bits
+ // to distinguish it from one less than that value.
+ if ((int)InputSize > MantissaWidth) {
+ // Conversion would lose accuracy. Check if loss can impact comparison.
+ int Exp = ilogb(RHS);
+ if (Exp == APFloat::IEK_Inf) {
+ int MaxExponent = ilogb(APFloat::getLargest(RHS.getSemantics()));
+ if (MaxExponent < (int)InputSize - !LHSUnsigned)
+ // Conversion could create infinity.
+ return nullptr;
+ } else {
+ // Note that if RHS is zero or NaN, then Exp is negative
+ // and first condition is trivially false.
+ if (MantissaWidth <= Exp && Exp <= (int)InputSize - !LHSUnsigned)
+ // Conversion could affect comparison.
+ return nullptr;
+ }
+ }
// Otherwise, we can potentially simplify the comparison. We know that it
// will always come through as an integer value and we know the constant is
}
; CHECK-LABEL: @i32_cast_cmp_oeq_int_n0_uitofp(
-; CHECK: uitofp
-; CHECK: fcmp oeq
+; CHECK-NEXT: icmp eq i32 %i, 0
+; CHECK-NEXT: ret
define i1 @i32_cast_cmp_oeq_int_n0_uitofp(i32 %i) {
%f = uitofp i32 %i to float
%cmp = fcmp oeq float %f, -0.0
}
; CHECK-LABEL: @i32_cast_cmp_oeq_int_n0_sitofp(
-; CHECK: sitofp
-; CHECK: fcmp oeq
+; CHECK-NEXT: icmp eq i32 %i, 0
+; CHECK-NEXT: ret
define i1 @i32_cast_cmp_oeq_int_n0_sitofp(i32 %i) {
%f = sitofp i32 %i to float
%cmp = fcmp oeq float %f, -0.0
}
; CHECK-LABEL: @i32_cast_cmp_one_int_n0_uitofp(
-; CHECK: uitofp
-; CHECK: fcmp one
+; CHECK-NEXT: icmp ne i32 %i, 0
+; CHECK-NEXT: ret
define i1 @i32_cast_cmp_one_int_n0_uitofp(i32 %i) {
%f = uitofp i32 %i to float
%cmp = fcmp one float %f, -0.0
}
; CHECK-LABEL: @i32_cast_cmp_one_int_n0_sitofp(
-; CHECK: sitofp
-; CHECK: fcmp one
+; CHECK-NEXT: icmp ne i32 %i, 0
+; CHECK-NEXT: ret
define i1 @i32_cast_cmp_one_int_n0_sitofp(i32 %i) {
%f = sitofp i32 %i to float
%cmp = fcmp one float %f, -0.0
}
; CHECK-LABEL: @i32_cast_cmp_ueq_int_n0_uitofp(
-; CHECK: uitofp
-; CHECK: fcmp ueq
+; CHECK-NEXT: icmp eq i32 %i, 0
+; CHECK-NEXT: ret
define i1 @i32_cast_cmp_ueq_int_n0_uitofp(i32 %i) {
%f = uitofp i32 %i to float
%cmp = fcmp ueq float %f, -0.0
}
; CHECK-LABEL: @i32_cast_cmp_ueq_int_n0_sitofp(
-; CHECK: sitofp
-; CHECK: fcmp ueq
+; CHECK-NEXT: icmp eq i32 %i, 0
+; CHECK-NEXT: ret
define i1 @i32_cast_cmp_ueq_int_n0_sitofp(i32 %i) {
%f = sitofp i32 %i to float
%cmp = fcmp ueq float %f, -0.0
}
; CHECK-LABEL: @i32_cast_cmp_une_int_n0_uitofp(
-; CHECK: uitofp
-; CHECK: fcmp une
+; CHECK-NEXT: icmp ne i32 %i, 0
+; CHECK-NEXT: ret
define i1 @i32_cast_cmp_une_int_n0_uitofp(i32 %i) {
%f = uitofp i32 %i to float
%cmp = fcmp une float %f, -0.0
}
; CHECK-LABEL: @i32_cast_cmp_une_int_n0_sitofp(
-; CHECK: sitofp
-; CHECK: fcmp une
+; CHECK-NEXT: icmp ne i32 %i, 0
+; CHECK-NEXT: ret
define i1 @i32_cast_cmp_une_int_n0_sitofp(i32 %i) {
%f = sitofp i32 %i to float
%cmp = fcmp une float %f, -0.0
}
; CHECK-LABEL: @i32_cast_cmp_ogt_int_n0_uitofp(
-; CHECK: uitofp
-; CHECK: fcmp ogt
+; CHECK: icmp ne i32 %i, 0
+; CHECK-NEXT: ret
define i1 @i32_cast_cmp_ogt_int_n0_uitofp(i32 %i) {
%f = uitofp i32 %i to float
%cmp = fcmp ogt float %f, -0.0
}
; CHECK-LABEL: @i32_cast_cmp_ogt_int_n0_sitofp(
-; CHECK: sitofp
-; CHECK: fcmp ogt
+; CHECK: icmp sgt i32 %i, 0
+; CHECK-NEXT: ret
define i1 @i32_cast_cmp_ogt_int_n0_sitofp(i32 %i) {
%f = sitofp i32 %i to float
%cmp = fcmp ogt float %f, -0.0
ret i1 %cmp
}
-; CHECK-LABEL: @i32_cast_cmp_oeq_int_i24max_uitofp(
-; CHECK: uitofp
-; CHECK: fcmp oeq
+; Since 0xFFFFFF fits in a float, and one less and
+; one more than it also fits without rounding, the
+; test can be optimized to an integer compare.
-; XCHECK: icmp eq i32 %i, 16777215
-; XCHECK-NEXT: ret
+; CHECK-LABEL: @i32_cast_cmp_oeq_int_i24max_uitofp(
+; CHECK: icmp eq i32 %i, 16777215
+; CHECK-NEXT: ret
define i1 @i32_cast_cmp_oeq_int_i24max_uitofp(i32 %i) {
%f = uitofp i32 %i to float
%cmp = fcmp oeq float %f, 0x416FFFFFE0000000
}
; CHECK-LABEL: @i32_cast_cmp_oeq_int_i24max_sitofp(
-; CHECK: sitofp
-; CHECK: fcmp oeq
-
-; XCHECK: icmp eq i32 %i, 16777215
-; XCHECK-NEXT: ret
+; CHECK: icmp eq i32 %i, 16777215
+; CHECK-NEXT: ret
define i1 @i32_cast_cmp_oeq_int_i24max_sitofp(i32 %i) {
%f = sitofp i32 %i to float
%cmp = fcmp oeq float %f, 0x416FFFFFE0000000
ret i1 %cmp
}
+; Though 0x1000000 fits in a float, one more than it
+; would round to it too, hence a single integer comparison
+; does not suffice.
+
; CHECK-LABEL: @i32_cast_cmp_oeq_int_i24maxp1_uitofp(
; CHECK: uitofp
; CHECK: fcmp oeq
ret i1 %cmp
}
+; 32-bit unsigned integer cannot possibly round up to 1<<33
+; CHECK-LABEL: @i32_cast_cmp_oeq_int_big_uitofp(
+; CHECK-NEXT: ret i1 false
+define i1 @i32_cast_cmp_oeq_int_big_uitofp(i32 %i) {
+ %f = uitofp i32 %i to float
+ %cmp = fcmp oeq float %f, 0x4200000000000000
+ ret i1 %cmp
+}
+
+; 32-bit signed integer cannot possibly round up to 1<<32
; CHECK-LABEL: @i32_cast_cmp_oeq_int_i32umax_sitofp(
-; CHECK: sitofp
-; CHECK: fcmp oeq
-; CHECK-NEXT: ret
+; CHECK-NEXT: ret i1 false
define i1 @i32_cast_cmp_oeq_int_i32umax_sitofp(i32 %i) {
%f = sitofp i32 %i to float
%cmp = fcmp oeq float %f, 0x41F0000000000000
ret i1 %cmp
}
+; 32-bit signed integer cannot possibly round to -1<<32
; CHECK-LABEL: @i32_cast_cmp_oeq_int_negi32umax_sitofp(
-; CHECK: sitofp
-; CHECK: fcmp oeq
-; CHECK-NEXT: ret
+; CHECK-NEXT: ret i1 false
define i1 @i32_cast_cmp_oeq_int_negi32umax_sitofp(i32 %i) {
%f = sitofp i32 %i to float
%cmp = fcmp oeq float %f, 0xC1F0000000000000
%cmp = fcmp une float %f, 0.5
ret i1 %cmp
}
+
+; CHECK-LABEL: @i32_cast_cmp_oeq_int_inf_uitofp(
+; CHECK-NEXT: ret i1 false
+define i1 @i32_cast_cmp_oeq_int_inf_uitofp(i32 %i) {
+ %f = uitofp i32 %i to float
+ %cmp = fcmp oeq float %f, 0x7FF0000000000000
+ ret i1 %cmp
+}
+
+; CHECK-LABEL: @i32_cast_cmp_oeq_int_inf_sitofp(
+; CHECK-NEXT: ret i1 false
+define i1 @i32_cast_cmp_oeq_int_inf_sitofp(i32 %i) {
+ %f = sitofp i32 %i to float
+ %cmp = fcmp oeq float %f, 0x7FF0000000000000
+ ret i1 %cmp
+}
+
+; An i128 could round to an IEEE single-precision infinity.
+; CHECK-LABEL: @i128_cast_cmp_oeq_int_inf_uitofp(
+; CHECK: uitofp
+; CHECK: fcmp oeq
+; CHECK-NEXT: ret
+define i1 @i128_cast_cmp_oeq_int_inf_uitofp(i128 %i) {
+ %f = uitofp i128 %i to float
+ %cmp = fcmp oeq float %f, 0x7FF0000000000000
+ ret i1 %cmp
+}