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llvm-svn: 56391
This commit is contained in:
Chris Lattner 2008-09-20 19:17:53 +00:00
parent 68f5000738
commit c018045520
1 changed files with 32 additions and 1 deletions
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33
lib/Target/X86/README-SSE.txt
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@ -17,7 +17,7 @@ other fast SSE modes.
//===---------------------------------------------------------------------===//
Think about doing i64 math in SSE regs.
Think about doing i64 math in SSE regs on x86-32.
//===---------------------------------------------------------------------===//
@ -876,3 +876,34 @@ orpd %xmm1, %xmm0 // 2^52 + x in double precision
subsd %xmm1, %xmm0 // x in double precision
cvtsd2ss %xmm0, %xmm0 // x in single precision
//===---------------------------------------------------------------------===//
rdar://5907648
This function:
float foo(unsigned char x) {
return x;
}
compiles to (x86-32):
define float @foo(i8 zeroext %x) nounwind {
%tmp12 = uitofp i8 %x to float ; <float> [#uses=1]
ret float %tmp12
}
compiles to:
_foo:
subl $4, %esp
movzbl 8(%esp), %eax
cvtsi2ss %eax, %xmm0
movss %xmm0, (%esp)
flds (%esp)
addl $4, %esp
ret
We should be able to use:
cvtsi2ss 8($esp), %xmm0
since we know the stack slot is already zext'd.