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Nikita Popov 3ff2f152d1 [InstCombine] Don't simplify calls without uses
When simplifying a call without uses, replaceInstUsesWith() is
going to do nothing, but we'll skip all following folds. We can
only run into this problem with calls that both simplify and are
not trivially dead if unused, which currently seems to happen only
with calls to undef, as the test diff shows. When extending
SimplifyCall() to handle "returned" attributes, this becomes a much
bigger problem, so I'm fixing this first.

Differential Revision: https://reviews.llvm.org/D75814
2020-03-09 18:47:46 +01:00

192 lines
7.6 KiB
LLVM

; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
; RUN: opt -S -instcombine -instcombine-infinite-loop-threshold=2 < %s | FileCheck %s
; This used to cause on infinite instcombine loop.
define void @test(i1 %c) {
; CHECK-LABEL: @test(
; CHECK-NEXT: bb16:
; CHECK-NEXT: br i1 [[C:%.*]], label [[BB17:%.*]], label [[BB24:%.*]]
; CHECK: bb17:
; CHECK-NEXT: [[TMP0:%.*]] = phi i8* [ [[TMP1:%.*]], [[BB47:%.*]] ], [ undef, [[BB16:%.*]] ]
; CHECK-NEXT: store i8* [[TMP0]], i8** undef, align 8
; CHECK-NEXT: ret void
; CHECK: bb24:
; CHECK-NEXT: br i1 [[C]], label [[BB44:%.*]], label [[BB49:%.*]]
; CHECK: bb44:
; CHECK-NEXT: [[TMP467:%.*]] = load i8*, i8** inttoptr (i64 16 to i8**), align 16
; CHECK-NEXT: br label [[BB47]]
; CHECK: bb47:
; CHECK-NEXT: [[TMP1]] = phi i8* [ [[TMP2:%.*]], [[BB150:%.*]] ], [ [[TMP1221:%.*]], [[BB119:%.*]] ], [ [[TMP1032:%.*]], [[BB101:%.*]] ], [ [[TMP933:%.*]], [[BB91:%.*]] ], [ [[TMP834:%.*]], [[BB81:%.*]] ], [ [[TMP705:%.*]], [[BB67:%.*]] ], [ [[TMP586:%.*]], [[BB56:%.*]] ], [ [[TMP467]], [[BB44]] ]
; CHECK-NEXT: br label [[BB17]]
; CHECK: bb49:
; CHECK-NEXT: br i1 [[C]], label [[BB56]], label [[BB59:%.*]]
; CHECK: bb56:
; CHECK-NEXT: [[TMP586]] = load i8*, i8** inttoptr (i64 16 to i8**), align 16
; CHECK-NEXT: br label [[BB47]]
; CHECK: bb59:
; CHECK-NEXT: br i1 [[C]], label [[BB67]], label [[BB71:%.*]]
; CHECK: bb67:
; CHECK-NEXT: [[TMP705]] = load i8*, i8** inttoptr (i64 16 to i8**), align 16
; CHECK-NEXT: br label [[BB47]]
; CHECK: bb71:
; CHECK-NEXT: br i1 [[C]], label [[BB81]], label [[BB84:%.*]]
; CHECK: bb81:
; CHECK-NEXT: [[TMP834]] = load i8*, i8** inttoptr (i64 16 to i8**), align 16
; CHECK-NEXT: br label [[BB47]]
; CHECK: bb84:
; CHECK-NEXT: br i1 [[C]], label [[BB91]], label [[BB94:%.*]]
; CHECK: bb91:
; CHECK-NEXT: [[TMP933]] = load i8*, i8** inttoptr (i64 16 to i8**), align 16
; CHECK-NEXT: br label [[BB47]]
; CHECK: bb94:
; CHECK-NEXT: br i1 [[C]], label [[BB101]], label [[BB104:%.*]]
; CHECK: bb101:
; CHECK-NEXT: [[TMP1032]] = load i8*, i8** inttoptr (i64 16 to i8**), align 16
; CHECK-NEXT: br label [[BB47]]
; CHECK: bb104:
; CHECK-NEXT: br i1 [[C]], label [[BB119]], label [[BB123:%.*]]
; CHECK: bb119:
; CHECK-NEXT: [[TMP1221]] = load i8*, i8** inttoptr (i64 16 to i8**), align 16
; CHECK-NEXT: br label [[BB47]]
; CHECK: bb123:
; CHECK-NEXT: br i1 [[C]], label [[BB147:%.*]], label [[BB152:%.*]]
; CHECK: bb147:
; CHECK-NEXT: [[TMP1499:%.*]] = load i8*, i8** inttoptr (i64 16 to i8**), align 16
; CHECK-NEXT: br label [[BB150]]
; CHECK: bb150:
; CHECK-NEXT: [[TMP2]] = phi i8* [ [[TMP1848:%.*]], [[BB152]] ], [ [[TMP1499]], [[BB147]] ]
; CHECK-NEXT: br label [[BB47]]
; CHECK: bb152:
; CHECK-NEXT: [[TMP1848]] = load i8*, i8** inttoptr (i64 16 to i8**), align 16
; CHECK-NEXT: store i1 true, i1* undef, align 1
; CHECK-NEXT: br label [[BB150]]
;
bb16: ; preds = %bb
br i1 %c, label %bb17, label %bb24
bb17: ; preds = %bb47, %bb17
%0 = phi i8* [ %1, %bb47 ], [ undef, %bb16 ]
store i8* %0, i8** undef, align 8
ret void
bb24: ; preds = %bb24
br i1 %c, label %bb44, label %bb49
bb44: ; preds = %bb43
%tmp46 = load i64*, i64** inttoptr (i64 16 to i64**), align 16
br label %bb47
bb47: ; preds = %bb150, %bb119, %bb101, %bb91, %bb81, %bb67, %bb56, %bb44
%.in1 = phi i64* [ %.in, %bb150 ], [ %tmp122, %bb119 ], [ %tmp103, %bb101 ], [ %tmp93, %bb91 ], [ %tmp83, %bb81 ], [ %tmp70, %bb67 ], [ %tmp58, %bb56 ], [ %tmp46, %bb44 ]
%1 = bitcast i64* %.in1 to i8*
br label %bb17
bb49: ; preds = %bb49
br i1 %c, label %bb56, label %bb59
bb56: ; preds = %bb55
%tmp58 = load i64*, i64** inttoptr (i64 16 to i64**), align 16
br label %bb47
bb59: ; preds = %bb59
br i1 %c, label %bb67, label %bb71
bb67: ; preds = %bb66
%tmp70 = load i64*, i64** inttoptr (i64 16 to i64**), align 16
br label %bb47
bb71: ; preds = %bb71
br i1 %c, label %bb81, label %bb84
bb81: ; preds = %bb80
%tmp83 = load i64*, i64** inttoptr (i64 16 to i64**), align 16
br label %bb47
bb84: ; preds = %bb84
br i1 %c, label %bb91, label %bb94
bb91: ; preds = %bb90
%tmp93 = load i64*, i64** inttoptr (i64 16 to i64**), align 16
br label %bb47
bb94: ; preds = %bb94
br i1 %c, label %bb101, label %bb104
bb101: ; preds = %bb100
%tmp103 = load i64*, i64** inttoptr (i64 16 to i64**), align 16
br label %bb47
bb104: ; preds = %bb104
br i1 %c, label %bb119, label %bb123
bb119: ; preds = %bb118
%tmp122 = load i64*, i64** inttoptr (i64 16 to i64**), align 16
br label %bb47
bb123: ; preds = %bb123
br i1 %c, label %bb147, label %bb152
bb147: ; preds = %bb146
%tmp149 = load i64*, i64** inttoptr (i64 16 to i64**), align 16
br label %bb150
bb150: ; preds = %bb152, %bb147
%.in = phi i64* [ %tmp184, %bb152 ], [ %tmp149, %bb147 ]
br label %bb47
bb152: ; preds = %bb146
%tmp184 = load i64*, i64** inttoptr (i64 16 to i64**), align 16
call void undef()
br label %bb150
}
; This used to cause an instcombine loop when the problem above was
; addressed in a non-robust fashion.
%type_1 = type {}
%type_2 = type {}
%type_3 = type {}
define void @test_2(i1 %c) local_unnamed_addr {
; CHECK-LABEL: @test_2(
; CHECK-NEXT: entry:
; CHECK-NEXT: br label [[WHILE_COND:%.*]]
; CHECK: while.cond:
; CHECK-NEXT: br label [[FOR_COND:%.*]]
; CHECK: for.cond:
; CHECK-NEXT: br i1 [[C:%.*]], label [[COND_TRUE133:%.*]], label [[COND_FALSE138:%.*]]
; CHECK: cond.true133:
; CHECK-NEXT: br label [[COND_END144:%.*]]
; CHECK: cond.false138:
; CHECK-NEXT: store %type_2* undef, %type_2** null, align 536870912
; CHECK-NEXT: br label [[COND_END144]]
; CHECK: cond.end144:
; CHECK-NEXT: br label [[WHILE_COND]]
;
entry:
br label %while.cond
while.cond: ; preds = %cond.end144, %entry
%link.0 = phi %type_2* [ undef, %entry ], [ %cond145, %cond.end144 ]
%os115 = bitcast %type_2* %link.0 to %type_3*
%ou116 = getelementptr inbounds %type_3, %type_3* %os115, i32 0
%os1117 = bitcast %type_3* %ou116 to %type_1*
br label %for.cond
for.cond: ; preds = %while.cond
br i1 %c, label %cond.true133, label %cond.false138
cond.true133: ; preds = %sw.epilog
%0 = load %type_2*, %type_2** undef, align 8
br label %cond.end144
cond.false138: ; preds = %sw.epilog
%1 = load %type_2*, %type_2** undef, align 8
br label %cond.end144
cond.end144: ; preds = %cond.false138, %cond.true133
%cond145 = phi %type_2* [ %0, %cond.true133 ], [ %1, %cond.false138 ]
br label %while.cond
}