Commit Graph

10 Commits

Author SHA1 Message Date
Dan Gohman
61a9213440 Implement an x86-64 ABI detail of passing structs by hidden first
argument. The x86-64 ABI requires the incoming value of %rdi to
be copied to %rax on exit from a function that is returning a
large C struct.

Also, add a README-X86-64 entry detailing the missed optimization
opportunity and proposing an alternative approach.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@50075 91177308-0d34-0410-b5e6-96231b3b80d8
2008-04-21 23:59:07 +00:00
Chris Lattner
b09916bdfb Make X86TargetLowering::LowerSINT_TO_FP return without creating a dead
stack slot and store if the  SINT_TO_FP is actually legal.  This allows
us to compile:

double a(double b) {return (unsigned)b;}

to:

_a:
	cvttsd2siq	%xmm0, %rax
	movl	%eax, %eax
	cvtsi2sdq	%rax, %xmm0
	ret

instead of:

_a:
	subq	$8, %rsp
	cvttsd2siq	%xmm0, %rax
	movl	%eax, %eax
	cvtsi2sdq	%rax, %xmm0
	addq	$8, %rsp
	ret

crazy.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@47660 91177308-0d34-0410-b5e6-96231b3b80d8
2008-02-27 05:57:41 +00:00
Chris Lattner
22eedf4eec this code is correct but strange looking ;-)
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@47659 91177308-0d34-0410-b5e6-96231b3b80d8
2008-02-27 05:48:44 +00:00
Chris Lattner
d0ba2a9c14 Compile x86-64-and-mask.ll into:
_test:
	movl	%edi, %eax
	ret

instead of:

_test:
        movl    $4294967295, %ecx
        movq    %rdi, %rax
        andq    %rcx, %rax
        ret

It would be great to write this as a Pat pattern that used subregs 
instead of a 'pseudo' instruction, but I don't know how to do that
in td files.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@47658 91177308-0d34-0410-b5e6-96231b3b80d8
2008-02-27 05:47:54 +00:00
Chris Lattner
ba309d43aa add a note
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@47652 91177308-0d34-0410-b5e6-96231b3b80d8
2008-02-27 01:17:20 +00:00
Evan Cheng
f7ef26e701 divb / mulb outputs to ah. Under x86-64 it's not legal to read ah if the instruction requires a rex prefix (i.e. outputs to r8b, etc.). So issue shift right by 8 on AX and then truncate it to 8 bits instead.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@40972 91177308-0d34-0410-b5e6-96231b3b80d8
2007-08-09 21:59:35 +00:00
Chris Lattner
e9a61234ce Dan pointed out that this is done, remove it!
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@35430 91177308-0d34-0410-b5e6-96231b3b80d8
2007-03-28 17:26:52 +00:00
Evan Cheng
28b51439f3 - Switch X86-64 JIT to large code size model.
- Re-enable some codegen niceties for X86-64 static relocation model codegen.
- Clean ups, etc.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@32238 91177308-0d34-0410-b5e6-96231b3b80d8
2006-12-05 19:50:18 +00:00
Evan Cheng
d9ff60b955 Update
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@32214 91177308-0d34-0410-b5e6-96231b3b80d8
2006-12-05 03:58:23 +00:00
Evan Cheng
25ab690a43 Committing X86-64 support.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@30177 91177308-0d34-0410-b5e6-96231b3b80d8
2006-09-08 06:48:29 +00:00