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llvm-project/llvm/test/CodeGen/X86/fp-in-intregs.ll

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Implement some dag combines that allow doing fneg/fabs/fcopysign in integer registers if used by a bitconvert or using a bitconvert. This allows us to avoid constant pool loads and use cheaper integer instructions when the values come from or end up in integer regs anyway. For example, we now compile CodeGen/X86/fp-in-intregs.ll to: _test1: movl $2147483648, %eax xorl 4(%esp), %eax ret _test2: movl $1065353216, %eax orl 4(%esp), %eax andl $3212836864, %eax ret Instead of: _test1: movss 4(%esp), %xmm0 xorps LCPI2_0, %xmm0 movd %xmm0, %eax ret _test2: movss 4(%esp), %xmm0 andps LCPI3_0, %xmm0 movss LCPI3_1, %xmm1 andps LCPI3_2, %xmm1 orps %xmm0, %xmm1 movd %xmm1, %eax ret bitconverts can happen due to various calling conventions that require fp values to passed in integer regs in some cases, e.g. when returning a complex. llvm-svn: 46414
2008-01-28 01:42:27 +08:00
; RUN: llvm-as < %s | llc -march=x86 -mcpu=yonah | not egrep {\(\(xor\|and\)ps\|movd\)}
; These operations should be done in integer registers, eliminating constant
; pool loads, movd's etc.
define i32 @test1(float %x) nounwind {
entry:
Split the Add, Sub, and Mul instruction opcodes into separate integer and floating-point opcodes, introducing FAdd, FSub, and FMul. For now, the AsmParser, BitcodeReader, and IRBuilder all preserve backwards compatability, and the Core LLVM APIs preserve backwards compatibility for IR producers. Most front-ends won't need to change immediately. This implements the first step of the plan outlined here: http://nondot.org/sabre/LLVMNotes/IntegerOverflow.txt llvm-svn: 72897
2009-06-05 06:49:04 +08:00
%tmp2 = fsub float -0.000000e+00, %x ; <float> [#uses=1]
Implement some dag combines that allow doing fneg/fabs/fcopysign in integer registers if used by a bitconvert or using a bitconvert. This allows us to avoid constant pool loads and use cheaper integer instructions when the values come from or end up in integer regs anyway. For example, we now compile CodeGen/X86/fp-in-intregs.ll to: _test1: movl $2147483648, %eax xorl 4(%esp), %eax ret _test2: movl $1065353216, %eax orl 4(%esp), %eax andl $3212836864, %eax ret Instead of: _test1: movss 4(%esp), %xmm0 xorps LCPI2_0, %xmm0 movd %xmm0, %eax ret _test2: movss 4(%esp), %xmm0 andps LCPI3_0, %xmm0 movss LCPI3_1, %xmm1 andps LCPI3_2, %xmm1 orps %xmm0, %xmm1 movd %xmm1, %eax ret bitconverts can happen due to various calling conventions that require fp values to passed in integer regs in some cases, e.g. when returning a complex. llvm-svn: 46414
2008-01-28 01:42:27 +08:00
%tmp210 = bitcast float %tmp2 to i32 ; <i32> [#uses=1]
ret i32 %tmp210
}
define i32 @test2(float %x) nounwind {
entry:
%tmp2 = tail call float @copysignf( float 1.000000e+00, float %x ) nounwind readnone ; <float> [#uses=1]
%tmp210 = bitcast float %tmp2 to i32 ; <i32> [#uses=1]
ret i32 %tmp210
}
declare float @copysignf(float, float) nounwind readnone