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llvm-project/llvm/test/Transforms/PGOProfile/counter_promo_mexits.ll

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[PGO] Enhance pgo counter promotion This is an incremental change to the promotion feature. There are two problems with the current behavior: 1) loops with multiple exiting blocks are totally disabled 2) a counter update can only be promoted one level up in the loop nest -- which does help much for short trip count inner loops inside a high trip-count outer loops. Due to this limitation, we still saw very large profile count fluctuations from run to run for the affected loops which are usually very hot. This patch adds the support for promotion counters iteratively across the loop nest. It also turns on the promotion for loops with multiple exiting blocks (with a limit). For single-threaded applications, the performance impact is flat on average. For instance, dealII improves, but povray regresses. llvm-svn: 307863
2017-07-13 07:27:44 +08:00
; RUN: opt < %s -pgo-instr-gen -instrprof -do-counter-promotion=true -speculative-counter-promotion-max-exiting=3 -S | FileCheck --check-prefix=PROMO %s
; RUN: opt < %s --passes=pgo-instr-gen,instrprof -do-counter-promotion=true -speculative-counter-promotion-max-exiting=3 -S | FileCheck --check-prefix=PROMO %s
[PGO] Implementate profile counter regiser promotion Differential Revision: http://reviews.llvm.org/D34085 llvm-svn: 306231
2017-06-25 08:26:43 +08:00
@g = common local_unnamed_addr global i32 0, align 4
define void @foo(i32 %arg) local_unnamed_addr {
; PROMO-LABEL: @foo
bb:
%tmp = add nsw i32 %arg, -1
br label %bb1
bb1: ; preds = %bb11, %bb
%tmp2 = phi i32 [ 0, %bb ], [ %tmp12, %bb11 ]
%tmp3 = icmp sgt i32 %tmp2, %arg
br i1 %tmp3, label %bb7, label %bb4
bb4: ; preds = %bb1
tail call void @bar(i32 1)
%tmp5 = load i32, i32* @g, align 4
%tmp6 = icmp sgt i32 %tmp5, 100
br i1 %tmp6, label %bb15_0, label %bb11
bb7: ; preds = %bb1
%tmp8 = icmp slt i32 %tmp2, %tmp
br i1 %tmp8, label %bb9, label %bb10
bb9: ; preds = %bb7
tail call void @bar(i32 2)
br label %bb11
bb10: ; preds = %bb7
tail call void @bar(i32 3)
br label %bb11
bb11: ; preds = %bb10, %bb9, %bb4
%tmp12 = add nuw nsw i32 %tmp2, 1
%tmp13 = icmp slt i32 %tmp2, 99
br i1 %tmp13, label %bb1, label %bb14
bb14: ; preds = %bb11
; PROMO-LABEL: bb14:
tail call void @bar(i32 0)
br label %bb15
; PROMO: %pgocount.promoted{{.*}} = load {{.*}} @__profc_foo{{.*}} 0)
; PROMO-NEXT: add
; PROMO-NEXT: store {{.*}}@__profc_foo{{.*}}0)
; PROMO-NEXT: %pgocount.promoted{{.*}} = load {{.*}} @__profc_foo{{.*}} 1)
; PROMO-NEXT: add
; PROMO-NEXT: store {{.*}}@__profc_foo{{.*}}1)
; PROMO-NEXT: %pgocount.promoted{{.*}} = load {{.*}} @__profc_foo{{.*}} 2)
; PROMO-NEXT: add
; PROMO-NEXT: store {{.*}}@__profc_foo{{.*}}2)
; PROMO-NEXT: %pgocount{{.*}} = load {{.*}} @__profc_foo{{.*}} 3)
; PROMO-NEXT: add
; PROMO-NEXT: store {{.*}}@__profc_foo{{.*}}3)
bb15_0: ; preds = %bb11
; PROMO-LABEL: bb15_0:
br label %bb15
; PROMO: %pgocount.promoted{{.*}} = load {{.*}} @__profc_foo{{.*}} 0)
; PROMO-NEXT: add
; PROMO-NEXT: store {{.*}}@__profc_foo{{.*}}0)
; PROMO-NEXT: %pgocount.promoted{{.*}} = load {{.*}} @__profc_foo{{.*}} 1)
; PROMO-NEXT: add
; PROMO-NEXT: store {{.*}}@__profc_foo{{.*}}1)
; PROMO-NEXT: %pgocount.promoted{{.*}} = load {{.*}} @__profc_foo{{.*}} 2)
; PROMO-NEXT: add
; PROMO-NEXT: store {{.*}}@__profc_foo{{.*}}2)
; PROMO-NEXT: %pgocount{{.*}} = load {{.*}} @__profc_foo{{.*}} 4)
; PROMO-NEXT: add
; PROMO-NEXT: store {{.*}}@__profc_foo{{.*}}4)
; PROMO-NOT: @__profc_foo
bb15: ; preds = %bb14, %bb4
tail call void @bar(i32 1)
ret void
}
declare void @bar(i32) local_unnamed_addr