; NOTE: Assertions have been autogenerated by utils/update_test_checks.py ; RUN: llc -mtriple=x86_64-unknown-unknown < %s | FileCheck %s ; cmp with single-use load, should not form branch. define i32 @test1(double %a, double* nocapture %b, i32 %x, i32 %y) { ; CHECK-LABEL: test1: ; CHECK: # BB#0: ; CHECK-NEXT: ucomisd (%rdi), %xmm0 ; CHECK-NEXT: cmovbel %edx, %esi ; CHECK-NEXT: movl %esi, %eax ; CHECK-NEXT: retq ; %load = load double, double* %b, align 8 %cmp = fcmp olt double %load, %a %cond = select i1 %cmp, i32 %x, i32 %y ret i32 %cond } ; Sanity check: no load. define i32 @test2(double %a, double %b, i32 %x, i32 %y) { ; CHECK-LABEL: test2: ; CHECK: # BB#0: ; CHECK-NEXT: ucomisd %xmm1, %xmm0 ; CHECK-NEXT: cmovbel %esi, %edi ; CHECK-NEXT: movl %edi, %eax ; CHECK-NEXT: retq ; %cmp = fcmp ogt double %a, %b %cond = select i1 %cmp, i32 %x, i32 %y ret i32 %cond } ; Multiple uses of the load. define i32 @test4(i32 %a, i32* nocapture %b, i32 %x, i32 %y) { ; CHECK-LABEL: test4: ; CHECK: # BB#0: ; CHECK-NEXT: movl (%rsi), %eax ; CHECK-NEXT: cmpl %edi, %eax ; CHECK-NEXT: cmovael %ecx, %edx ; CHECK-NEXT: addl %edx, %eax ; CHECK-NEXT: retq ; %load = load i32, i32* %b, align 4 %cmp = icmp ult i32 %load, %a %cond = select i1 %cmp, i32 %x, i32 %y %add = add i32 %cond, %load ret i32 %add } ; Multiple uses of the cmp. define i32 @test5(i32 %a, i32* nocapture %b, i32 %x, i32 %y) { ; CHECK-LABEL: test5: ; CHECK: # BB#0: ; CHECK-NEXT: cmpl %edi, (%rsi) ; CHECK-NEXT: cmoval %edi, %ecx ; CHECK-NEXT: cmovael %edx, %ecx ; CHECK-NEXT: movl %ecx, %eax ; CHECK-NEXT: retq ; %load = load i32, i32* %b, align 4 %cmp = icmp ult i32 %load, %a %cmp1 = icmp ugt i32 %load, %a %cond = select i1 %cmp1, i32 %a, i32 %y %cond5 = select i1 %cmp, i32 %cond, i32 %x ret i32 %cond5 } ; If a select is not obviously predictable, don't turn it into a branch. define i32 @weighted_select1(i32 %a, i32 %b) { ; CHECK-LABEL: weighted_select1: ; CHECK: # BB#0: ; CHECK-NEXT: testl %edi, %edi ; CHECK-NEXT: cmovnel %edi, %esi ; CHECK-NEXT: movl %esi, %eax ; CHECK-NEXT: retq ; %cmp = icmp ne i32 %a, 0 %sel = select i1 %cmp, i32 %a, i32 %b, !prof !0 ret i32 %sel } ; 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: 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 %sel = select i1 %cmp, i32 %a, i32 %b, !prof !1 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 } ; Weightlessness is no reason to die. define i32 @unweighted_select(i32 %a, i32 %b) { ; CHECK-LABEL: unweighted_select: ; CHECK: # BB#0: ; CHECK-NEXT: testl %edi, %edi ; CHECK-NEXT: cmovnel %edi, %esi ; CHECK-NEXT: movl %esi, %eax ; CHECK-NEXT: retq ; %cmp = icmp ne i32 %a, 0 %sel = select i1 %cmp, i32 %a, i32 %b, !prof !3 ret i32 %sel } !0 = !{!"branch_weights", i32 1, i32 99} !1 = !{!"branch_weights", i32 1, i32 100} !2 = !{!"branch_weights", i32 100, i32 1} !3 = !{!"branch_weights", i32 0, i32 0}