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llvm-mirror/test/Analysis/MemorySSA/cyclicphi.ll
Manoj Gupta 647946fa14 llvm: Add support for "-fno-delete-null-pointer-checks"
Summary:
Support for this option is needed for building Linux kernel.
This is a very frequently requested feature by kernel developers.

More details : https://lkml.org/lkml/2018/4/4/601

GCC option description for -fdelete-null-pointer-checks:
This Assume that programs cannot safely dereference null pointers,
and that no code or data element resides at address zero.

-fno-delete-null-pointer-checks is the inverse of this implying that
null pointer dereferencing is not undefined.

This feature is implemented in LLVM IR in this CL as the function attribute
"null-pointer-is-valid"="true" in IR (Under review at D47894).
The CL updates several passes that assumed null pointer dereferencing is
undefined to not optimize when the "null-pointer-is-valid"="true"
attribute is present.

Reviewers: t.p.northover, efriedma, jyknight, chandlerc, rnk, srhines, void, george.burgess.iv

Reviewed By: efriedma, george.burgess.iv

Subscribers: eraman, haicheng, george.burgess.iv, drinkcat, theraven, reames, sanjoy, xbolva00, llvm-commits

Differential Revision: https://reviews.llvm.org/D47895

llvm-svn: 336613
2018-07-09 22:27:23 +00:00

156 lines
6.0 KiB
LLVM

; RUN: opt -basicaa -print-memoryssa -verify-memoryssa -analyze < %s 2>&1 | FileCheck %s
; RUN: opt -aa-pipeline=basic-aa -passes='print<memoryssa>,verify<memoryssa>' -disable-output < %s 2>&1 | FileCheck %s
%struct.hoge = type { i32, %struct.widget }
%struct.widget = type { i64 }
define hidden void @quux(%struct.hoge *%f) align 2 {
%tmp = getelementptr inbounds %struct.hoge, %struct.hoge* %f, i64 0, i32 1, i32 0
%tmp24 = getelementptr inbounds %struct.hoge, %struct.hoge* %f, i64 0, i32 1
%tmp25 = bitcast %struct.widget* %tmp24 to i64**
br label %bb26
bb26: ; preds = %bb77, %0
; CHECK: 3 = MemoryPhi({%0,liveOnEntry},{bb77,2})
; CHECK-NEXT: br i1 undef, label %bb68, label %bb77
br i1 undef, label %bb68, label %bb77
bb68: ; preds = %bb26
; CHECK: MemoryUse(liveOnEntry)
; CHECK-NEXT: %tmp69 = load i64, i64* null, align 8
%tmp69 = load i64, i64* null, align 8
; CHECK: 1 = MemoryDef(3)
; CHECK-NEXT: store i64 %tmp69, i64* %tmp, align 8
store i64 %tmp69, i64* %tmp, align 8
br label %bb77
bb77: ; preds = %bb68, %bb26
; CHECK: 2 = MemoryPhi({bb26,3},{bb68,1})
; CHECK: MemoryUse(2)
; CHECK-NEXT: %tmp78 = load i64*, i64** %tmp25, align 8
%tmp78 = load i64*, i64** %tmp25, align 8
%tmp79 = getelementptr inbounds i64, i64* %tmp78, i64 undef
br label %bb26
}
define hidden void @quux_no_null_opt(%struct.hoge *%f) align 2 #0 {
; CHECK-LABEL: quux_no_null_opt(
%tmp = getelementptr inbounds %struct.hoge, %struct.hoge* %f, i64 0, i32 1, i32 0
%tmp24 = getelementptr inbounds %struct.hoge, %struct.hoge* %f, i64 0, i32 1
%tmp25 = bitcast %struct.widget* %tmp24 to i64**
br label %bb26
bb26: ; preds = %bb77, %0
; CHECK: 3 = MemoryPhi({%0,liveOnEntry},{bb77,2})
; CHECK-NEXT: br i1 undef, label %bb68, label %bb77
br i1 undef, label %bb68, label %bb77
bb68: ; preds = %bb26
; CHECK: MemoryUse(3)
; CHECK-NEXT: %tmp69 = load i64, i64* null, align 8
%tmp69 = load i64, i64* null, align 8
; CHECK: 1 = MemoryDef(3)
; CHECK-NEXT: store i64 %tmp69, i64* %tmp, align 8
store i64 %tmp69, i64* %tmp, align 8
br label %bb77
bb77: ; preds = %bb68, %bb26
; CHECK: 2 = MemoryPhi({bb26,3},{bb68,1})
; CHECK: MemoryUse(2)
; CHECK-NEXT: %tmp78 = load i64*, i64** %tmp25, align 8
%tmp78 = load i64*, i64** %tmp25, align 8
%tmp79 = getelementptr inbounds i64, i64* %tmp78, i64 undef
br label %bb26
}
; CHECK-LABEL: define void @quux_skip
define void @quux_skip(%struct.hoge* noalias %f, i64* noalias %g) align 2 {
%tmp = getelementptr inbounds %struct.hoge, %struct.hoge* %f, i64 0, i32 1, i32 0
%tmp24 = getelementptr inbounds %struct.hoge, %struct.hoge* %f, i64 0, i32 1
%tmp25 = bitcast %struct.widget* %tmp24 to i64**
br label %bb26
bb26: ; preds = %bb77, %0
; CHECK: 3 = MemoryPhi({%0,liveOnEntry},{bb77,2})
; CHECK-NEXT: br i1 undef, label %bb68, label %bb77
br i1 undef, label %bb68, label %bb77
bb68: ; preds = %bb26
; CHECK: MemoryUse(3)
; CHECK-NEXT: %tmp69 = load i64, i64* %g, align 8
%tmp69 = load i64, i64* %g, align 8
; CHECK: 1 = MemoryDef(3)
; CHECK-NEXT: store i64 %tmp69, i64* %g, align 8
store i64 %tmp69, i64* %g, align 8
br label %bb77
bb77: ; preds = %bb68, %bb26
; CHECK: 2 = MemoryPhi({bb26,3},{bb68,1})
; CHECK: MemoryUse(liveOnEntry)
; CHECK-NEXT: %tmp78 = load i64*, i64** %tmp25, align 8
%tmp78 = load i64*, i64** %tmp25, align 8
br label %bb26
}
; CHECK-LABEL: define void @quux_dominated
define void @quux_dominated(%struct.hoge* noalias %f, i64* noalias %g) align 2 {
%tmp = getelementptr inbounds %struct.hoge, %struct.hoge* %f, i64 0, i32 1, i32 0
%tmp24 = getelementptr inbounds %struct.hoge, %struct.hoge* %f, i64 0, i32 1
%tmp25 = bitcast %struct.widget* %tmp24 to i64**
br label %bb26
bb26: ; preds = %bb77, %0
; CHECK: 3 = MemoryPhi({%0,liveOnEntry},{bb77,2})
; CHECK: MemoryUse(3)
; CHECK-NEXT: load i64*, i64** %tmp25, align 8
load i64*, i64** %tmp25, align 8
br i1 undef, label %bb68, label %bb77
bb68: ; preds = %bb26
; CHECK: MemoryUse(3)
; CHECK-NEXT: %tmp69 = load i64, i64* %g, align 8
%tmp69 = load i64, i64* %g, align 8
; CHECK: 1 = MemoryDef(3)
; CHECK-NEXT: store i64 %tmp69, i64* %g, align 8
store i64 %tmp69, i64* %g, align 8
br label %bb77
bb77: ; preds = %bb68, %bb26
; CHECK: 4 = MemoryPhi({bb26,3},{bb68,1})
; CHECK: 2 = MemoryDef(4)
; CHECK-NEXT: store i64* null, i64** %tmp25, align 8
store i64* null, i64** %tmp25, align 8
br label %bb26
}
; CHECK-LABEL: define void @quux_nodominate
define void @quux_nodominate(%struct.hoge* noalias %f, i64* noalias %g) align 2 {
%tmp = getelementptr inbounds %struct.hoge, %struct.hoge* %f, i64 0, i32 1, i32 0
%tmp24 = getelementptr inbounds %struct.hoge, %struct.hoge* %f, i64 0, i32 1
%tmp25 = bitcast %struct.widget* %tmp24 to i64**
br label %bb26
bb26: ; preds = %bb77, %0
; CHECK: 3 = MemoryPhi({%0,liveOnEntry},{bb77,2})
; CHECK: MemoryUse(liveOnEntry)
; CHECK-NEXT: load i64*, i64** %tmp25, align 8
load i64*, i64** %tmp25, align 8
br i1 undef, label %bb68, label %bb77
bb68: ; preds = %bb26
; CHECK: MemoryUse(3)
; CHECK-NEXT: %tmp69 = load i64, i64* %g, align 8
%tmp69 = load i64, i64* %g, align 8
; CHECK: 1 = MemoryDef(3)
; CHECK-NEXT: store i64 %tmp69, i64* %g, align 8
store i64 %tmp69, i64* %g, align 8
br label %bb77
bb77: ; preds = %bb68, %bb26
; CHECK: 2 = MemoryPhi({bb26,3},{bb68,1})
; CHECK-NEXT: br label %bb26
br label %bb26
}
attributes #0 = { "null-pointer-is-valid"="true" }