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llvm-svn: 42785
This commit is contained in:
Dan Gohman 2007-10-09 15:42:21 +00:00
parent 708e76e663
commit 9546d48e97
1 changed files with 0 additions and 30 deletions
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lib/Target/X86/README.txt
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@ -10,36 +10,6 @@ http://softwarecommunity.intel.com/isn/Downloads/Intel%20SSE4%20Programming%20Re
//===---------------------------------------------------------------------===//
Add a MUL2U and MUL2S nodes to represent a multiply that returns both the
Hi and Lo parts (combination of MUL and MULH[SU] into one node). Add this to
X86, & make the dag combiner produce it when needed. This will eliminate one
imul from the code generated for:
long long test(long long X, long long Y) { return X*Y; }
by using the EAX result from the mul. We should add a similar node for
DIVREM.
another case is:
long long test(int X, int Y) { return (long long)X*Y; }
... which should only be one imul instruction.
or:
unsigned long long int t2(unsigned int a, unsigned int b) {
return (unsigned long long)a * b;
}
... which should be one mul instruction.
This can be done with a custom expander, but it would be nice to move this to
generic code.
//===---------------------------------------------------------------------===//
CodeGen/X86/lea-3.ll:test3 should be a single LEA, not a shift/move. The X86
backend knows how to three-addressify this shift, but it appears the register
allocator isn't even asking it to do so in this case. We should investigate