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llvm-mirror/test/Transforms/SimplifyCFG/speculatively-execute-block-profmd.ll
Roman Lebedev cc6967667d [SimplifyCFG] Don't speculatively execute BB if it's predictably not taken 
If the branch isn't `unpredictable`, and it is predicted to *not* branch
to the block we are considering speculatively executing,
then it seems counter-productive to execute the code that is predicted not to be executed.

Reviewed By: spatel

Differential Revision: https://reviews.llvm.org/D106650
2021-07-26 02:55:14 +03:00

261 lines
8.4 KiB
LLVM
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; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
; RUN: opt -S -simplifycfg -simplifycfg-require-and-preserve-domtree=1 -two-entry-phi-node-folding-threshold=0 -phi-node-folding-threshold=4 < %s | FileCheck %s
declare void @sideeffect0()
declare void @sideeffect1()
declare void @sideeffect2()
define i32 @unknown(i1 %c, i32 %a, i32 %b) {
; CHECK-LABEL: @unknown(
; CHECK-NEXT: entry:
; CHECK-NEXT: call void @sideeffect0()
; CHECK-NEXT: br i1 [[C:%.*]], label [[DISPATCH:%.*]], label [[END:%.*]]
; CHECK: dispatch:
; CHECK-NEXT: call void @sideeffect1()
; CHECK-NEXT: [[CMP:%.*]] = icmp eq i32 [[A:%.*]], [[B:%.*]]
; CHECK-NEXT: [[VAL:%.*]] = add i32 [[A]], [[B]]
; CHECK-NEXT: [[SPEC_SELECT:%.*]] = select i1 [[CMP]], i32 [[VAL]], i32 0
; CHECK-NEXT: br label [[END]]
; CHECK: end:
; CHECK-NEXT: [[RES:%.*]] = phi i32 [ -1, [[ENTRY:%.*]] ], [ [[SPEC_SELECT]], [[DISPATCH]] ]
; CHECK-NEXT: call void @sideeffect2()
; CHECK-NEXT: ret i32 [[RES]]
;
entry:
call void @sideeffect0()
br i1 %c, label %dispatch, label %end
dispatch:
call void @sideeffect1()
%cmp = icmp eq i32 %a, %b
br i1 %cmp, label %cond.true, label %end
cond.true:
%val = add i32 %a, %b
br label %end
end:
%res = phi i32 [ -1, %entry ], [ 0, %dispatch ], [ %val, %cond.true ]
call void @sideeffect2()
ret i32 %res
}
define i32 @predictably_taken(i1 %c, i32 %a, i32 %b) {
; CHECK-LABEL: @predictably_taken(
; CHECK-NEXT: entry:
; CHECK-NEXT: call void @sideeffect0()
; CHECK-NEXT: br i1 [[C:%.*]], label [[DISPATCH:%.*]], label [[END:%.*]]
; CHECK: dispatch:
; CHECK-NEXT: call void @sideeffect1()
; CHECK-NEXT: [[CMP:%.*]] = icmp eq i32 [[A:%.*]], [[B:%.*]]
; CHECK-NEXT: [[VAL:%.*]] = add i32 [[A]], [[B]]
; CHECK-NEXT: [[SPEC_SELECT:%.*]] = select i1 [[CMP]], i32 [[VAL]], i32 0, !prof [[PROF0:![0-9]+]]
; CHECK-NEXT: br label [[END]]
; CHECK: end:
; CHECK-NEXT: [[RES:%.*]] = phi i32 [ -1, [[ENTRY:%.*]] ], [ [[SPEC_SELECT]], [[DISPATCH]] ]
; CHECK-NEXT: call void @sideeffect2()
; CHECK-NEXT: ret i32 [[RES]]
;
entry:
call void @sideeffect0()
br i1 %c, label %dispatch, label %end
dispatch:
call void @sideeffect1()
%cmp = icmp eq i32 %a, %b
br i1 %cmp, label %cond.true, label %end, !prof !0 ; likely branches to %cond.true
cond.true:
%val = add i32 %a, %b
br label %end
end:
%res = phi i32 [ -1, %entry ], [ 0, %dispatch ], [ %val, %cond.true ]
call void @sideeffect2()
ret i32 %res
}
define i32 @predictably_nontaken(i1 %c, i32 %a, i32 %b) {
; CHECK-LABEL: @predictably_nontaken(
; CHECK-NEXT: entry:
; CHECK-NEXT: call void @sideeffect0()
; CHECK-NEXT: br i1 [[C:%.*]], label [[DISPATCH:%.*]], label [[END:%.*]]
; CHECK: dispatch:
; CHECK-NEXT: call void @sideeffect1()
; CHECK-NEXT: [[CMP:%.*]] = icmp eq i32 [[A:%.*]], [[B:%.*]]
; CHECK-NEXT: br i1 [[CMP]], label [[END]], label [[COND_TRUE:%.*]], !prof [[PROF0]]
; CHECK: cond.true:
; CHECK-NEXT: [[VAL:%.*]] = add i32 [[A]], [[B]]
; CHECK-NEXT: br label [[END]]
; CHECK: end:
; CHECK-NEXT: [[RES:%.*]] = phi i32 [ -1, [[ENTRY:%.*]] ], [ 0, [[DISPATCH]] ], [ [[VAL]], [[COND_TRUE]] ]
; CHECK-NEXT: call void @sideeffect2()
; CHECK-NEXT: ret i32 [[RES]]
;
entry:
call void @sideeffect0()
br i1 %c, label %dispatch, label %end
dispatch:
call void @sideeffect1()
%cmp = icmp eq i32 %a, %b
br i1 %cmp, label %end, label %cond.true, !prof !0 ; likely branches to %end
cond.true:
%val = add i32 %a, %b
br label %end
end:
%res = phi i32 [ -1, %entry ], [ 0, %dispatch ], [ %val, %cond.true ]
call void @sideeffect2()
ret i32 %res
}
define i32 @almost_predictably_nontaken(i1 %c, i32 %a, i32 %b) {
; CHECK-LABEL: @almost_predictably_nontaken(
; CHECK-NEXT: entry:
; CHECK-NEXT: call void @sideeffect0()
; CHECK-NEXT: br i1 [[C:%.*]], label [[DISPATCH:%.*]], label [[END:%.*]]
; CHECK: dispatch:
; CHECK-NEXT: call void @sideeffect1()
; CHECK-NEXT: [[CMP:%.*]] = icmp eq i32 [[A:%.*]], [[B:%.*]]
; CHECK-NEXT: [[VAL:%.*]] = add i32 [[A]], [[B]]
; CHECK-NEXT: [[SPEC_SELECT:%.*]] = select i1 [[CMP]], i32 0, i32 [[VAL]], !prof [[PROF1:![0-9]+]]
; CHECK-NEXT: br label [[END]]
; CHECK: end:
; CHECK-NEXT: [[RES:%.*]] = phi i32 [ -1, [[ENTRY:%.*]] ], [ [[SPEC_SELECT]], [[DISPATCH]] ]
; CHECK-NEXT: call void @sideeffect2()
; CHECK-NEXT: ret i32 [[RES]]
;
entry:
call void @sideeffect0()
br i1 %c, label %dispatch, label %end
dispatch:
call void @sideeffect1()
%cmp = icmp eq i32 %a, %b
br i1 %cmp, label %end, label %cond.true, !prof !1 ; almost likely branches to %end
cond.true:
%val = add i32 %a, %b
br label %end
end:
%res = phi i32 [ -1, %entry ], [ 0, %dispatch ], [ %val, %cond.true ]
call void @sideeffect2()
ret i32 %res
}
define i32 @unpredictable(i1 %c, i32 %a, i32 %b) {
; CHECK-LABEL: @unpredictable(
; CHECK-NEXT: entry:
; CHECK-NEXT: call void @sideeffect0()
; CHECK-NEXT: br i1 [[C:%.*]], label [[DISPATCH:%.*]], label [[END:%.*]]
; CHECK: dispatch:
; CHECK-NEXT: call void @sideeffect1()
; CHECK-NEXT: [[CMP:%.*]] = icmp eq i32 [[A:%.*]], [[B:%.*]]
; CHECK-NEXT: [[VAL:%.*]] = add i32 [[A]], [[B]]
; CHECK-NEXT: [[SPEC_SELECT:%.*]] = select i1 [[CMP]], i32 [[VAL]], i32 0, !unpredictable !2
; CHECK-NEXT: br label [[END]]
; CHECK: end:
; CHECK-NEXT: [[RES:%.*]] = phi i32 [ -1, [[ENTRY:%.*]] ], [ [[SPEC_SELECT]], [[DISPATCH]] ]
; CHECK-NEXT: call void @sideeffect2()
; CHECK-NEXT: ret i32 [[RES]]
;
entry:
call void @sideeffect0()
br i1 %c, label %dispatch, label %end
dispatch:
call void @sideeffect1()
%cmp = icmp eq i32 %a, %b
br i1 %cmp, label %cond.true, label %end, !unpredictable !2 ; unpredictable
cond.true:
%val = add i32 %a, %b
br label %end
end:
%res = phi i32 [ -1, %entry ], [ 0, %dispatch ], [ %val, %cond.true ]
call void @sideeffect2()
ret i32 %res
}
define i32 @unpredictable_yet_taken(i1 %c, i32 %a, i32 %b) {
; CHECK-LABEL: @unpredictable_yet_taken(
; CHECK-NEXT: entry:
; CHECK-NEXT: call void @sideeffect0()
; CHECK-NEXT: br i1 [[C:%.*]], label [[DISPATCH:%.*]], label [[END:%.*]]
; CHECK: dispatch:
; CHECK-NEXT: call void @sideeffect1()
; CHECK-NEXT: [[CMP:%.*]] = icmp eq i32 [[A:%.*]], [[B:%.*]]
; CHECK-NEXT: [[VAL:%.*]] = add i32 [[A]], [[B]]
; CHECK-NEXT: [[SPEC_SELECT:%.*]] = select i1 [[CMP]], i32 [[VAL]], i32 0, !prof [[PROF0]], !unpredictable !2
; CHECK-NEXT: br label [[END]]
; CHECK: end:
; CHECK-NEXT: [[RES:%.*]] = phi i32 [ -1, [[ENTRY:%.*]] ], [ [[SPEC_SELECT]], [[DISPATCH]] ]
; CHECK-NEXT: call void @sideeffect2()
; CHECK-NEXT: ret i32 [[RES]]
;
entry:
call void @sideeffect0()
br i1 %c, label %dispatch, label %end
dispatch:
call void @sideeffect1()
%cmp = icmp eq i32 %a, %b
br i1 %cmp, label %cond.true, label %end, !prof !0, !unpredictable !2 ; likely branches to %cond.true, yet unpredictable
cond.true:
%val = add i32 %a, %b
br label %end
end:
%res = phi i32 [ -1, %entry ], [ 0, %dispatch ], [ %val, %cond.true ]
call void @sideeffect2()
ret i32 %res
}
define i32 @unpredictable_yet_nontaken(i1 %c, i32 %a, i32 %b) {
; CHECK-LABEL: @unpredictable_yet_nontaken(
; CHECK-NEXT: entry:
; CHECK-NEXT: call void @sideeffect0()
; CHECK-NEXT: br i1 [[C:%.*]], label [[DISPATCH:%.*]], label [[END:%.*]]
; CHECK: dispatch:
; CHECK-NEXT: call void @sideeffect1()
; CHECK-NEXT: [[CMP:%.*]] = icmp eq i32 [[A:%.*]], [[B:%.*]]
; CHECK-NEXT: [[VAL:%.*]] = add i32 [[A]], [[B]]
; CHECK-NEXT: [[SPEC_SELECT:%.*]] = select i1 [[CMP]], i32 0, i32 [[VAL]], !prof [[PROF0]], !unpredictable !2
; CHECK-NEXT: br label [[END]]
; CHECK: end:
; CHECK-NEXT: [[RES:%.*]] = phi i32 [ -1, [[ENTRY:%.*]] ], [ [[SPEC_SELECT]], [[DISPATCH]] ]
; CHECK-NEXT: call void @sideeffect2()
; CHECK-NEXT: ret i32 [[RES]]
;
entry:
call void @sideeffect0()
br i1 %c, label %dispatch, label %end
dispatch:
call void @sideeffect1()
%cmp = icmp eq i32 %a, %b
br i1 %cmp, label %end, label %cond.true, !prof !0, !unpredictable !2 ; likely branches to %end, yet unpredictable
cond.true:
%val = add i32 %a, %b
br label %end
end:
%res = phi i32 [ -1, %entry ], [ 0, %dispatch ], [ %val, %cond.true ]
call void @sideeffect2()
ret i32 %res
}
!0 = !{!"branch_weights", i32 99, i32 1}
!1 = !{!"branch_weights", i32 70, i32 1}
!2 = !{}
; CHECK: !0 = !{!"branch_weights", i32 99, i32 1}
; CHECK: !1 = !{!"branch_weights", i32 70, i32 1}
; CHECK: !2 = !{}
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