136 lines
3.8 KiB
LLVM
136 lines
3.8 KiB
LLVM
; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
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; RUN: llc -mtriple=x86_64-unknown-unknown < %s | FileCheck %s
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; cmp with single-use load, should not form branch.
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define i32 @test1(double %a, double* nocapture %b, i32 %x, i32 %y) {
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; CHECK-LABEL: test1:
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; CHECK: # BB#0:
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; CHECK-NEXT: ucomisd (%rdi), %xmm0
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; CHECK-NEXT: cmovbel %edx, %esi
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; CHECK-NEXT: movl %esi, %eax
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; CHECK-NEXT: retq
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;
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%load = load double, double* %b, align 8
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%cmp = fcmp olt double %load, %a
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%cond = select i1 %cmp, i32 %x, i32 %y
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ret i32 %cond
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}
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; Sanity check: no load.
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define i32 @test2(double %a, double %b, i32 %x, i32 %y) {
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; CHECK-LABEL: test2:
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; CHECK: # BB#0:
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; CHECK-NEXT: ucomisd %xmm1, %xmm0
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; CHECK-NEXT: cmovbel %esi, %edi
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; CHECK-NEXT: movl %edi, %eax
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; CHECK-NEXT: retq
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;
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%cmp = fcmp ogt double %a, %b
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%cond = select i1 %cmp, i32 %x, i32 %y
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ret i32 %cond
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}
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; Multiple uses of the load.
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define i32 @test4(i32 %a, i32* nocapture %b, i32 %x, i32 %y) {
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; CHECK-LABEL: test4:
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; CHECK: # BB#0:
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; CHECK-NEXT: movl (%rsi), %eax
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; CHECK-NEXT: cmpl %edi, %eax
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; CHECK-NEXT: cmovael %ecx, %edx
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; CHECK-NEXT: addl %edx, %eax
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; CHECK-NEXT: retq
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;
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%load = load i32, i32* %b, align 4
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%cmp = icmp ult i32 %load, %a
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%cond = select i1 %cmp, i32 %x, i32 %y
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%add = add i32 %cond, %load
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ret i32 %add
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}
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; Multiple uses of the cmp.
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define i32 @test5(i32 %a, i32* nocapture %b, i32 %x, i32 %y) {
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; CHECK-LABEL: test5:
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; CHECK: # BB#0:
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; CHECK-NEXT: cmpl %edi, (%rsi)
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; CHECK-NEXT: cmoval %edi, %ecx
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; CHECK-NEXT: cmovael %edx, %ecx
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; CHECK-NEXT: movl %ecx, %eax
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; CHECK-NEXT: retq
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;
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%load = load i32, i32* %b, align 4
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%cmp = icmp ult i32 %load, %a
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%cmp1 = icmp ugt i32 %load, %a
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%cond = select i1 %cmp1, i32 %a, i32 %y
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%cond5 = select i1 %cmp, i32 %cond, i32 %x
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ret i32 %cond5
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}
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; If a select is not obviously predictable, don't turn it into a branch.
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define i32 @weighted_select1(i32 %a, i32 %b) {
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; CHECK-LABEL: weighted_select1:
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; CHECK: # BB#0:
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; CHECK-NEXT: testl %edi, %edi
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; CHECK-NEXT: cmovnel %edi, %esi
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; CHECK-NEXT: movl %esi, %eax
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; CHECK-NEXT: retq
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;
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%cmp = icmp ne i32 %a, 0
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%sel = select i1 %cmp, i32 %a, i32 %b, !prof !0
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ret i32 %sel
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}
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; If a select is obviously predictable, turn it into a branch.
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define i32 @weighted_select2(i32 %a, i32 %b) {
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; CHECK-LABEL: weighted_select2:
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; CHECK: # BB#0:
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; CHECK-NEXT: testl %edi, %edi
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; CHECK-NEXT: jne [[LABEL_BB5:.*]]
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; CHECK: movl %esi, %edi
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; CHECK-NEXT: [[LABEL_BB5]]
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; CHECK-NEXT: movl %edi, %eax
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; CHECK-NEXT: retq
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;
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%cmp = icmp ne i32 %a, 0
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%sel = select i1 %cmp, i32 %a, i32 %b, !prof !1
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ret i32 %sel
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}
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; Note the reversed profile weights: it doesn't matter if it's
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; obviously true or obviously false.
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; Either one should become a branch rather than conditional move.
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; TODO: But likely true vs. likely false should affect basic block placement?
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define i32 @weighted_select3(i32 %a, i32 %b) {
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; CHECK-LABEL: weighted_select3:
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; CHECK: # BB#0:
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; CHECK-NEXT: testl %edi, %edi
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; CHECK-NEXT: jne [[LABEL_BB6:.*]]
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; CHECK: movl %esi, %edi
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; CHECK-NEXT: [[LABEL_BB6]]
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; CHECK-NEXT: movl %edi, %eax
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; CHECK-NEXT: retq
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;
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%cmp = icmp ne i32 %a, 0
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%sel = select i1 %cmp, i32 %a, i32 %b, !prof !2
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ret i32 %sel
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}
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; Weightlessness is no reason to die.
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define i32 @unweighted_select(i32 %a, i32 %b) {
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; CHECK-LABEL: unweighted_select:
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; CHECK: # BB#0:
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; CHECK-NEXT: testl %edi, %edi
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; CHECK-NEXT: cmovnel %edi, %esi
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; CHECK-NEXT: movl %esi, %eax
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; CHECK-NEXT: retq
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;
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%cmp = icmp ne i32 %a, 0
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%sel = select i1 %cmp, i32 %a, i32 %b, !prof !3
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ret i32 %sel
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}
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!0 = !{!"branch_weights", i32 1, i32 99}
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!1 = !{!"branch_weights", i32 1, i32 100}
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!2 = !{!"branch_weights", i32 100, i32 1}
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!3 = !{!"branch_weights", i32 0, i32 0}
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