diff options
| -rw-r--r-- | lib/Target/X86/README.txt | 28 |
1 files changed, 28 insertions, 0 deletions
diff --git a/lib/Target/X86/README.txt b/lib/Target/X86/README.txt index 1902485c18..8237fbd094 100644 --- a/lib/Target/X86/README.txt +++ b/lib/Target/X86/README.txt @@ -2032,3 +2032,31 @@ clamp_float: # @clamp_float with -ffast-math. //===---------------------------------------------------------------------===// + +This function (from PR9803): + +int clamp2(int a) { + if (a > 5) + a = 5; + if (a < 0) + return 0; + return a; +} + +Compiles to: + +_clamp2: ## @clamp2 + pushq %rbp + movq %rsp, %rbp + cmpl $5, %edi + movl $5, %ecx + cmovlel %edi, %ecx + testl %ecx, %ecx + movl $0, %eax + cmovnsl %ecx, %eax + popq %rbp + ret + +The move of 0 could be scheduled above the test to make it is xor reg,reg. + +//===---------------------------------------------------------------------===// |