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llvm-project/llvm/test/Transforms/SCCP/ipsccp-predinfo-order.ll

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[PredicateInfo] Replace pointer comparisons with deterministic compares. Currently there are a few pointer comparisons in ValueDFS_Compare, which can cause non-deterministic ordering when materializing values. There are 2 cases this patch fixes: 1. Order defs before uses used to compare pointers, which guarantees defs before uses, but causes non-deterministic ordering between 2 uses or 2 defs, depending on the allocation order. By converting the pointers to booleans, we can circumvent that problem. 2. comparePHIRelated was comparing the basic block pointers of edges, which also results in a non-deterministic order and is also not really meaningful for ordering. By ordering by their destination DFS numbers we guarantee a deterministic order. For the example below, we can end up with 2 different uselist orderings, when running `opt -mem2reg -ipsccp` hundreds of times. Because the non-determinism is caused by allocation ordering, we cannot reproduce it with ipsccp alone. declare i32 @hoge() local_unnamed_addr #0 define dso_local i32 @ham(i8* %arg, i8* %arg1) #0 { bb: %tmp = alloca i32 %tmp2 = alloca i32, align 4 br label %bb19 bb4: ; preds = %bb20 br label %bb6 bb6: ; preds = %bb4 %tmp7 = call i32 @hoge() store i32 %tmp7, i32* %tmp %tmp8 = load i32, i32* %tmp %tmp9 = icmp eq i32 %tmp8, 912730082 %tmp10 = load i32, i32* %tmp br i1 %tmp9, label %bb11, label %bb16 bb11: ; preds = %bb6 unreachable bb13: ; preds = %bb20 br label %bb14 bb14: ; preds = %bb13 %tmp15 = load i32, i32* %tmp br label %bb16 bb16: ; preds = %bb14, %bb6 %tmp17 = phi i32 [ %tmp10, %bb6 ], [ 0, %bb14 ] br label %bb19 bb18: ; preds = %bb20 unreachable bb19: ; preds = %bb16, %bb br label %bb20 bb20: ; preds = %bb19 indirectbr i8* null, [label %bb4, label %bb13, label %bb18] } Reviewers: davide, efriedma Reviewed By: efriedma Differential Revision: https://reviews.llvm.org/D64866 llvm-svn: 367049
2019-07-26 04:48:13 +08:00
; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
; RUN: opt -ipsccp -S %s | FileCheck %s
declare i32 @hoge()
define dso_local i32 @ham(i8* %arg, i8* %arg1) {
; CHECK-LABEL: @ham(
; CHECK-NEXT: bb:
; CHECK-NEXT: [[TMP:%.*]] = alloca i32
; CHECK-NEXT: [[TMP2:%.*]] = alloca i32, align 4
; CHECK-NEXT: br label [[BB19:%.*]]
; CHECK: bb4:
; CHECK-NEXT: br label [[BB6:%.*]]
; CHECK: bb6:
; CHECK-NEXT: [[TMP7:%.*]] = call i32 @hoge()
; CHECK-NEXT: store i32 [[TMP7]], i32* [[TMP]]
; CHECK-NEXT: [[TMP8:%.*]] = load i32, i32* [[TMP]]
; CHECK-NEXT: [[TMP9:%.*]] = icmp eq i32 [[TMP8]], 912730082
; CHECK-NEXT: [[TMP10:%.*]] = load i32, i32* [[TMP]]
; CHECK-NEXT: br i1 [[TMP9]], label [[BB11:%.*]], label [[BB16:%.*]]
; CHECK: bb11:
; CHECK-NEXT: unreachable
; CHECK: bb13:
; CHECK-NEXT: br label [[BB14:%.*]]
; CHECK: bb14:
; CHECK-NEXT: [[TMP15:%.*]] = load i32, i32* [[TMP]]
; CHECK-NEXT: br label [[BB16]]
; CHECK: bb16:
; CHECK-NEXT: [[TMP17:%.*]] = phi i32 [ [[TMP10]], [[BB6]] ], [ 0, [[BB14]] ]
; CHECK-NEXT: br label [[BB19]]
; CHECK: bb18:
; CHECK-NEXT: unreachable
; CHECK: bb19:
; CHECK-NEXT: br label [[BB20:%.*]]
; CHECK: bb20:
; CHECK-NEXT: indirectbr i8* null, [label [[BB4:%.*]], label [[BB13:%.*]], label %bb18]
;
bb:
%tmp = alloca i32
%tmp2 = alloca i32, align 4
br label %bb19
bb4: ; preds = %bb20
br label %bb6
bb6: ; preds = %bb4
%tmp7 = call i32 @hoge()
store i32 %tmp7, i32* %tmp
%tmp8 = load i32, i32* %tmp
%tmp9 = icmp eq i32 %tmp8, 912730082
%tmp10 = load i32, i32* %tmp
br i1 %tmp9, label %bb11, label %bb16
bb11: ; preds = %bb6
unreachable
bb13: ; preds = %bb20
br label %bb14
bb14: ; preds = %bb13
%tmp15 = load i32, i32* %tmp
br label %bb16
bb16: ; preds = %bb14, %bb6
%tmp17 = phi i32 [ %tmp10, %bb6 ], [ 0, %bb14 ]
br label %bb19
bb18: ; preds = %bb20
unreachable
bb19: ; preds = %bb16, %bb
br label %bb20
bb20: ; preds = %bb19
indirectbr i8* null, [label %bb4, label %bb13, label %bb18]
}