77eeac3d9e
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
231 lines
5.2 KiB
LLVM
231 lines
5.2 KiB
LLVM
; RUN: opt < %s -correlated-propagation -S | FileCheck %s
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define void @test1(i8* %ptr) {
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; CHECK: test1
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%A = load i8, i8* %ptr
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br label %bb
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bb:
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icmp ne i8* %ptr, null
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; CHECK-NOT: icmp
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ret void
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}
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define void @test1_no_null_opt(i8* %ptr) #0 {
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; CHECK: test1_no_null_opt
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%A = load i8, i8* %ptr
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br label %bb
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bb:
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icmp ne i8* %ptr, null
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; CHECK: icmp ne i8* %ptr, null
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ret void
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}
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define void @test2(i8* %ptr) {
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; CHECK: test2
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store i8 0, i8* %ptr
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br label %bb
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bb:
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icmp ne i8* %ptr, null
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; CHECK-NOT: icmp
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ret void
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}
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define void @test2_no_null_opt(i8* %ptr) #0 {
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; CHECK: test2_no_null_opt
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store i8 0, i8* %ptr
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br label %bb
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bb:
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icmp ne i8* %ptr, null
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; CHECK: icmp ne i8* %ptr, null
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ret void
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}
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define void @test3() {
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; CHECK: test3
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%ptr = alloca i8
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br label %bb
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bb:
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icmp ne i8* %ptr, null
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; CHECK-NOT: icmp
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ret void
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}
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;; OK to remove icmp here since ptr is coming from alloca.
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define void @test3_no_null_opt() #0 {
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; CHECK: test3
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%ptr = alloca i8
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br label %bb
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bb:
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icmp ne i8* %ptr, null
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; CHECK-NOT: icmp
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ret void
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}
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declare void @llvm.memcpy.p0i8.p0i8.i32(i8*, i8*, i32, i1)
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define void @test4(i8* %dest, i8* %src) {
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; CHECK: test4
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call void @llvm.memcpy.p0i8.p0i8.i32(i8* %dest, i8* %src, i32 1, i1 false)
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br label %bb
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bb:
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icmp ne i8* %dest, null
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icmp ne i8* %src, null
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; CHECK-NOT: icmp
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ret void
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}
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define void @test4_no_null_opt(i8* %dest, i8* %src) #0 {
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; CHECK: test4_no_null_opt
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call void @llvm.memcpy.p0i8.p0i8.i32(i8* %dest, i8* %src, i32 1, i1 false)
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br label %bb
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bb:
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icmp ne i8* %dest, null
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icmp ne i8* %src, null
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; CHECK: icmp ne i8* %dest, null
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; CHECK: icmp ne i8* %src, null
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ret void
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}
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declare void @llvm.memmove.p0i8.p0i8.i32(i8*, i8*, i32, i1)
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define void @test5(i8* %dest, i8* %src) {
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; CHECK: test5
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call void @llvm.memmove.p0i8.p0i8.i32(i8* %dest, i8* %src, i32 1, i1 false)
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br label %bb
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bb:
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icmp ne i8* %dest, null
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icmp ne i8* %src, null
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; CHECK-NOT: icmp
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ret void
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}
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define void @test5_no_null_opt(i8* %dest, i8* %src) #0 {
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; CHECK: test5_no_null_opt
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call void @llvm.memmove.p0i8.p0i8.i32(i8* %dest, i8* %src, i32 1, i1 false)
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br label %bb
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bb:
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icmp ne i8* %dest, null
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icmp ne i8* %src, null
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; CHECK: icmp ne i8* %dest, null
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; CHECK: icmp ne i8* %src, null
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ret void
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}
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declare void @llvm.memset.p0i8.i32(i8*, i8, i32, i1)
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define void @test6(i8* %dest) {
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; CHECK: test6
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call void @llvm.memset.p0i8.i32(i8* %dest, i8 255, i32 1, i1 false)
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br label %bb
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bb:
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icmp ne i8* %dest, null
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; CHECK-NOT: icmp
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ret void
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}
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define void @test6_no_null_opt(i8* %dest) #0 {
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; CHECK: test6_no_null_opt
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call void @llvm.memset.p0i8.i32(i8* %dest, i8 255, i32 1, i1 false)
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br label %bb
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bb:
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icmp ne i8* %dest, null
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; CHECK: icmp ne i8* %dest, null
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ret void
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}
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define void @test7(i8* %dest, i8* %src, i32 %len) {
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; CHECK: test7
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call void @llvm.memcpy.p0i8.p0i8.i32(i8* %dest, i8* %src, i32 %len, i1 false)
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br label %bb
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bb:
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%KEEP1 = icmp ne i8* %dest, null
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; CHECK: KEEP1
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%KEEP2 = icmp ne i8* %src, null
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; CHECK: KEEP2
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ret void
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}
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declare void @llvm.memcpy.p1i8.p1i8.i32(i8 addrspace(1) *, i8 addrspace(1) *, i32, i1)
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define void @test8(i8 addrspace(1) * %dest, i8 addrspace(1) * %src) {
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; CHECK: test8
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call void @llvm.memcpy.p1i8.p1i8.i32(i8 addrspace(1) * %dest, i8 addrspace(1) * %src, i32 1, i1 false)
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br label %bb
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bb:
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%KEEP1 = icmp ne i8 addrspace(1) * %dest, null
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; CHECK: KEEP1
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%KEEP2 = icmp ne i8 addrspace(1) * %src, null
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; CHECK: KEEP2
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ret void
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}
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define void @test9(i8* %dest, i8* %src) {
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; CHECK: test9
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call void @llvm.memcpy.p0i8.p0i8.i32(i8* %dest, i8* %src, i32 1, i1 true)
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br label %bb
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bb:
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%KEEP1 = icmp ne i8* %dest, null
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; CHECK: KEEP1
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%KEEP2 = icmp ne i8* %src, null
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; CHECK: KEEP2
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ret void
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}
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declare void @test10_helper(i8* %arg1, i8* %arg2, i32 %non-pointer-arg)
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define void @test10(i8* %arg1, i8* %arg2, i32 %non-pointer-arg) {
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; CHECK-LABEL: @test10
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entry:
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%is_null = icmp eq i8* %arg1, null
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br i1 %is_null, label %null, label %non_null
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non_null:
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call void @test10_helper(i8* %arg1, i8* %arg2, i32 %non-pointer-arg)
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; CHECK: call void @test10_helper(i8* nonnull %arg1, i8* %arg2, i32 %non-pointer-arg)
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br label %null
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null:
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call void @test10_helper(i8* %arg1, i8* %arg2, i32 %non-pointer-arg)
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; CHECK: call void @test10_helper(i8* %arg1, i8* %arg2, i32 %non-pointer-arg)
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ret void
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}
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declare void @test11_helper(i8* %arg)
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define void @test11(i8* %arg1, i8** %arg2) {
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; CHECK-LABEL: @test11
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entry:
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%is_null = icmp eq i8* %arg1, null
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br i1 %is_null, label %null, label %non_null
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non_null:
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br label %merge
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null:
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%another_arg = alloca i8
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br label %merge
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merge:
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%merged_arg = phi i8* [%another_arg, %null], [%arg1, %non_null]
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call void @test11_helper(i8* %merged_arg)
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; CHECK: call void @test11_helper(i8* nonnull %merged_arg)
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ret void
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}
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declare void @test12_helper(i8* %arg)
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define void @test12(i8* %arg1, i8** %arg2) {
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; CHECK-LABEL: @test12
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entry:
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%is_null = icmp eq i8* %arg1, null
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br i1 %is_null, label %null, label %non_null
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non_null:
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br label %merge
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null:
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%another_arg = load i8*, i8** %arg2, !nonnull !{}
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br label %merge
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merge:
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%merged_arg = phi i8* [%another_arg, %null], [%arg1, %non_null]
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call void @test12_helper(i8* %merged_arg)
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; CHECK: call void @test12_helper(i8* nonnull %merged_arg)
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ret void
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}
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attributes #0 = { "null-pointer-is-valid"="true" }
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