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Diffstat (limited to 'lib/Target/X86/README-X86-64.txt')
| -rw-r--r-- | lib/Target/X86/README-X86-64.txt | 21 |
1 files changed, 0 insertions, 21 deletions
diff --git a/lib/Target/X86/README-X86-64.txt b/lib/Target/X86/README-X86-64.txt index 44c2e2894d..191904ac51 100644 --- a/lib/Target/X86/README-X86-64.txt +++ b/lib/Target/X86/README-X86-64.txt @@ -30,27 +30,6 @@ We need to do the tailcall optimization as well. //===---------------------------------------------------------------------===// -For this: - -int test(int a) -{ - return a * 3; -} - -We generates - leal (%edi,%edi,2), %eax - -We should be generating - leal (%rdi,%rdi,2), %eax - -instead. The later form does not require an address-size prefix 67H. - -It's probably ok to simply emit the corresponding 64-bit super class registers -in this case? - - -//===---------------------------------------------------------------------===// - AMD64 Optimization Manual 8.2 has some nice information about optimizing integer multiplication by a constant. How much of it applies to Intel's X86-64 implementation? There are definite trade-offs to consider: latency vs. register |