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DAG: Lower single infinity is.fpclass tests to fcmp (#100380)

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InstCombine also should have taken care of this, but this
should be helpful when the fcmp based lowering strategy tries
to combine multiple tests.
This commit is contained in:
Matt Arsenault 2024-09-06 09:15:18 +04:00 committed by GitHub
parent 8e35c86977
commit 77f1b481b8
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3 changed files with 54 additions and 56 deletions
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2
llvm/lib/CodeGen/CodeGenCommonISel.cpp
View File

@ -202,6 +202,8 @@ FPClassTest llvm::invertFPClassTestIfSimpler(FPClassTest Test, bool UseFCmp) {
case fcSubnormal | fcZero | fcNan:
return InvertedTest;
case fcInf | fcNan:
case fcPosInf | fcNan:
case fcNegInf | fcNan:
// If we're trying to use fcmp, we can take advantage of the nan check
// behavior of the compare (but this is more instructions in the integer
// expansion).

16
llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp
View File

@ -8754,6 +8754,22 @@ SDValue TargetLowering::expandIS_FPCLASS(EVT ResultVT, SDValue Op,
IsOrderedInf ? OrderedCmpOpcode : UnorderedCmpOpcode);
}
if ((OrderedFPTestMask == fcPosInf || OrderedFPTestMask == fcNegInf) &&
isCondCodeLegalOrCustom(IsOrdered ? OrderedCmpOpcode
: UnorderedCmpOpcode,
OperandVT.getSimpleVT())) {
// isposinf(x) --> x == inf
// isneginf(x) --> x == -inf
// isposinf(x) || nan --> x u== inf
// isneginf(x) || nan --> x u== -inf
SDValue Inf = DAG.getConstantFP(
APFloat::getInf(Semantics, OrderedFPTestMask == fcNegInf), DL,
OperandVT);
return DAG.getSetCC(DL, ResultVT, Op, Inf,
IsOrdered ? OrderedCmpOpcode : UnorderedCmpOpcode);
}
if (OrderedFPTestMask == (fcSubnormal | fcZero) && !IsOrdered) {
// TODO: Could handle ordered case, but it produces worse code for
// x86. Maybe handle ordered if fabs is free?

92
llvm/test/CodeGen/X86/is_fpclass.ll
View File

@ -2116,24 +2116,19 @@ entry:
define i1 @is_plus_inf_or_nan_f(float %x) {
; X86-LABEL: is_plus_inf_or_nan_f:
; X86: # %bb.0:
; X86-NEXT: movl {{[0-9]+}}(%esp), %eax
; X86-NEXT: cmpl $2139095040, %eax # imm = 0x7F800000
; X86-NEXT: sete %cl
; X86-NEXT: andl $2147483647, %eax # imm = 0x7FFFFFFF
; X86-NEXT: cmpl $2139095041, %eax # imm = 0x7F800001
; X86-NEXT: setge %al
; X86-NEXT: orb %cl, %al
; X86-NEXT: flds {{[0-9]+}}(%esp)
; X86-NEXT: flds {{\.?LCPI[0-9]+_[0-9]+}}
; X86-NEXT: fucompp
; X86-NEXT: fnstsw %ax
; X86-NEXT: # kill: def $ah killed $ah killed $ax
; X86-NEXT: sahf
; X86-NEXT: sete %al
; X86-NEXT: retl
;
; X64-LABEL: is_plus_inf_or_nan_f:
; X64: # %bb.0:
; X64-NEXT: movd %xmm0, %eax
; X64-NEXT: cmpl $2139095040, %eax # imm = 0x7F800000
; X64-NEXT: sete %cl
; X64-NEXT: andl $2147483647, %eax # imm = 0x7FFFFFFF
; X64-NEXT: cmpl $2139095041, %eax # imm = 0x7F800001
; X64-NEXT: setge %al
; X64-NEXT: orb %cl, %al
; X64-NEXT: ucomiss {{\.?LCPI[0-9]+_[0-9]+}}(%rip), %xmm0
; X64-NEXT: sete %al
; X64-NEXT: retq
%class = tail call i1 @llvm.is.fpclass.f32(float %x, i32 515) ; 0x200|0x3 = "+inf|nan"
ret i1 %class
@ -2142,24 +2137,19 @@ define i1 @is_plus_inf_or_nan_f(float %x) {
define i1 @is_minus_inf_or_nan_f(float %x) {
; X86-LABEL: is_minus_inf_or_nan_f:
; X86: # %bb.0:
; X86-NEXT: movl {{[0-9]+}}(%esp), %eax
; X86-NEXT: cmpl $-8388608, %eax # imm = 0xFF800000
; X86-NEXT: sete %cl
; X86-NEXT: andl $2147483647, %eax # imm = 0x7FFFFFFF
; X86-NEXT: cmpl $2139095041, %eax # imm = 0x7F800001
; X86-NEXT: setge %al
; X86-NEXT: orb %cl, %al
; X86-NEXT: flds {{[0-9]+}}(%esp)
; X86-NEXT: flds {{\.?LCPI[0-9]+_[0-9]+}}
; X86-NEXT: fucompp
; X86-NEXT: fnstsw %ax
; X86-NEXT: # kill: def $ah killed $ah killed $ax
; X86-NEXT: sahf
; X86-NEXT: sete %al
; X86-NEXT: retl
;
; X64-LABEL: is_minus_inf_or_nan_f:
; X64: # %bb.0:
; X64-NEXT: movd %xmm0, %eax
; X64-NEXT: cmpl $-8388608, %eax # imm = 0xFF800000
; X64-NEXT: sete %cl
; X64-NEXT: andl $2147483647, %eax # imm = 0x7FFFFFFF
; X64-NEXT: cmpl $2139095041, %eax # imm = 0x7F800001
; X64-NEXT: setge %al
; X64-NEXT: orb %cl, %al
; X64-NEXT: ucomiss {{\.?LCPI[0-9]+_[0-9]+}}(%rip), %xmm0
; X64-NEXT: sete %al
; X64-NEXT: retq
%class = tail call i1 @llvm.is.fpclass.f32(float %x, i32 7) ; "-inf|nan"
ret i1 %class
@ -2168,24 +2158,19 @@ define i1 @is_minus_inf_or_nan_f(float %x) {
define i1 @not_is_plus_inf_or_nan_f(float %x) {
; X86-LABEL: not_is_plus_inf_or_nan_f:
; X86: # %bb.0:
; X86-NEXT: movl {{[0-9]+}}(%esp), %eax
; X86-NEXT: cmpl $-8388608, %eax # imm = 0xFF800000
; X86-NEXT: sete %cl
; X86-NEXT: andl $2147483647, %eax # imm = 0x7FFFFFFF
; X86-NEXT: cmpl $2139095040, %eax # imm = 0x7F800000
; X86-NEXT: setl %al
; X86-NEXT: orb %cl, %al
; X86-NEXT: flds {{[0-9]+}}(%esp)
; X86-NEXT: flds {{\.?LCPI[0-9]+_[0-9]+}}
; X86-NEXT: fucompp
; X86-NEXT: fnstsw %ax
; X86-NEXT: # kill: def $ah killed $ah killed $ax
; X86-NEXT: sahf
; X86-NEXT: setne %al
; X86-NEXT: retl
;
; X64-LABEL: not_is_plus_inf_or_nan_f:
; X64: # %bb.0:
; X64-NEXT: movd %xmm0, %eax
; X64-NEXT: cmpl $-8388608, %eax # imm = 0xFF800000
; X64-NEXT: sete %cl
; X64-NEXT: andl $2147483647, %eax # imm = 0x7FFFFFFF
; X64-NEXT: cmpl $2139095040, %eax # imm = 0x7F800000
; X64-NEXT: setl %al
; X64-NEXT: orb %cl, %al
; X64-NEXT: ucomiss {{\.?LCPI[0-9]+_[0-9]+}}(%rip), %xmm0
; X64-NEXT: setne %al
; X64-NEXT: retq
%class = tail call i1 @llvm.is.fpclass.f32(float %x, i32 508) ; ~(0x200|0x3) = "~(+inf|nan)"
ret i1 %class
@ -2194,24 +2179,19 @@ define i1 @not_is_plus_inf_or_nan_f(float %x) {
define i1 @not_is_minus_inf_or_nan_f(float %x) {
; X86-LABEL: not_is_minus_inf_or_nan_f:
; X86: # %bb.0:
; X86-NEXT: movl {{[0-9]+}}(%esp), %eax
; X86-NEXT: cmpl $2139095040, %eax # imm = 0x7F800000
; X86-NEXT: sete %cl
; X86-NEXT: andl $2147483647, %eax # imm = 0x7FFFFFFF
; X86-NEXT: cmpl $2139095040, %eax # imm = 0x7F800000
; X86-NEXT: setl %al
; X86-NEXT: orb %cl, %al
; X86-NEXT: flds {{[0-9]+}}(%esp)
; X86-NEXT: flds {{\.?LCPI[0-9]+_[0-9]+}}
; X86-NEXT: fucompp
; X86-NEXT: fnstsw %ax
; X86-NEXT: # kill: def $ah killed $ah killed $ax
; X86-NEXT: sahf
; X86-NEXT: setne %al
; X86-NEXT: retl
;
; X64-LABEL: not_is_minus_inf_or_nan_f:
; X64: # %bb.0:
; X64-NEXT: movd %xmm0, %eax
; X64-NEXT: cmpl $2139095040, %eax # imm = 0x7F800000
; X64-NEXT: sete %cl
; X64-NEXT: andl $2147483647, %eax # imm = 0x7FFFFFFF
; X64-NEXT: cmpl $2139095040, %eax # imm = 0x7F800000
; X64-NEXT: setl %al
; X64-NEXT: orb %cl, %al
; X64-NEXT: ucomiss {{\.?LCPI[0-9]+_[0-9]+}}(%rip), %xmm0
; X64-NEXT: setne %al
; X64-NEXT: retq
%class = tail call i1 @llvm.is.fpclass.f32(float %x, i32 1016) ; "~(-inf|nan)"
ret i1 %class