Changes in directory llvm/lib/Target/X86:
README.txt updated: 1.106 -> 1.107 --- Log message: add a note --- Diffs of the changes: (+15 -0) README.txt | 15 +++++++++++++++ 1 files changed, 15 insertions(+) Index: llvm/lib/Target/X86/README.txt diff -u llvm/lib/Target/X86/README.txt:1.106 llvm/lib/Target/X86/README.txt:1.107 --- llvm/lib/Target/X86/README.txt:1.106 Wed May 17 16:20:51 2006 +++ llvm/lib/Target/X86/README.txt Thu May 18 12:38:16 2006 @@ -380,6 +380,21 @@ This may just be a matter of using 'test' to write bigger patterns for X86cmp. +An important case is comparison against zero: + +if (X == 0) ... + +instead of: + + cmpl $0, %eax + je LBB4_2 #cond_next + +use: + test %eax, %eax + jz LBB4_2 + +which is smaller. + //===---------------------------------------------------------------------===// SSE should implement 'select_cc' using 'emulated conditional moves' that use _______________________________________________ llvm-commits mailing list llvm-commits@cs.uiuc.edu http://lists.cs.uiuc.edu/mailman/listinfo/llvm-commits
