diff options
Diffstat (limited to 'llvm/test/CodeGen/X86/cmov-into-branch.ll')
| -rw-r--r-- | llvm/test/CodeGen/X86/cmov-into-branch.ll | 29 |
1 files changed, 26 insertions, 3 deletions
diff --git a/llvm/test/CodeGen/X86/cmov-into-branch.ll b/llvm/test/CodeGen/X86/cmov-into-branch.ll index 99aa4d51429..35c1d3498a5 100644 --- a/llvm/test/CodeGen/X86/cmov-into-branch.ll +++ b/llvm/test/CodeGen/X86/cmov-into-branch.ll @@ -79,13 +79,15 @@ define i32 @weighted_select1(i32 %a, i32 %b) { ret i32 %sel } -; TODO: If a select is obviously predictable, turn it into a branch. +; If a select is obviously predictable, turn it into a branch. define i32 @weighted_select2(i32 %a, i32 %b) { ; CHECK-LABEL: weighted_select2: ; CHECK: # BB#0: ; CHECK-NEXT: testl %edi, %edi -; CHECK-NEXT: cmovnel %edi, %esi -; CHECK-NEXT: movl %esi, %eax +; CHECK-NEXT: jne [[LABEL_BB5:.*]] +; CHECK: movl %esi, %edi +; CHECK-NEXT: [[LABEL_BB5]] +; CHECK-NEXT: movl %edi, %eax ; CHECK-NEXT: retq ; %cmp = icmp ne i32 %a, 0 @@ -93,6 +95,27 @@ define i32 @weighted_select2(i32 %a, i32 %b) { ret i32 %sel } +; Note the reversed profile weights: it doesn't matter if it's +; obviously true or obviously false. +; Either one should become a branch rather than conditional move. +; TODO: But likely true vs. likely false should affect basic block placement? +define i32 @weighted_select3(i32 %a, i32 %b) { +; CHECK-LABEL: weighted_select3: +; CHECK: # BB#0: +; CHECK-NEXT: testl %edi, %edi +; CHECK-NEXT: jne [[LABEL_BB6:.*]] +; CHECK: movl %esi, %edi +; CHECK-NEXT: [[LABEL_BB6]] +; CHECK-NEXT: movl %edi, %eax +; CHECK-NEXT: retq +; + %cmp = icmp ne i32 %a, 0 + %sel = select i1 %cmp, i32 %a, i32 %b, !prof !2 + ret i32 %sel +} + + !0 = !{!"branch_weights", i32 1, i32 99} !1 = !{!"branch_weights", i32 1, i32 100} +!2 = !{!"branch_weights", i32 100, i32 1} |
