diff options
| -rw-r--r-- | lib/Target/X86/README.txt | 16 |
1 files changed, 16 insertions, 0 deletions
diff --git a/lib/Target/X86/README.txt b/lib/Target/X86/README.txt index 81e9797..0fd79f2 100644 --- a/lib/Target/X86/README.txt +++ b/lib/Target/X86/README.txt @@ -1306,3 +1306,19 @@ However, ICC caches this information before the loop and produces this: movl 88(%esp), %eax #481.12 //===---------------------------------------------------------------------===// + +This code: + + %tmp659 = icmp slt i16 %tmp654, 0 ; <i1> [#uses=1] + br i1 %tmp659, label %cond_true662, label %cond_next715 + +produces this: + + testw %cx, %cx + movswl %cx, %esi + jns LBB4_109 # cond_next715 + +Shark tells us that using %cx in the testw instruction is sub-optimal. It +suggests using the 32-bit register (which is what ICC uses). + +//===---------------------------------------------------------------------===// |