llvm-project/llvm/test/Analysis/CFLAliasAnalysis/Steensgaard/branch-alias.ll

74 lines
2.3 KiB
LLVM

; Makes sure that we give up on some pathological cases with inttoptr/ptrtoint
;
; @ptr_test was generated from the following C code:
; void ptr_test() {
; int* A;
; unsigned long RefCopy = 0;
; for (int i = 0; i < 8*sizeof(&A); ++i) {
; if ((unsigned long)&A & (1UL << i))
; RefCopy |= 1UL << i;
; }
;
; int** AliasA1 = (int**)RefCopy;
; int* ShouldAliasA = *AliasA1;
; }
; RUN: opt < %s -disable-basicaa -cfl-steens-aa -aa-eval -print-may-aliases -disable-output 2>&1 | FileCheck %s
; CHECK: Function: ptr_test
define void @ptr_test() #0 {
; CHECK: MayAlias: i32** %A, i32** %ShouldAliasA
; CHECK-NOT: %AliasA1
entry:
%A = alloca i32*, align 8
%RefCopy = alloca i64, align 8
%i = alloca i32, align 4
%AliasA1 = alloca i32**, align 8
%ShouldAliasA = alloca i32*, align 8
store i64 0, i64* %RefCopy, align 8
store i32 0, i32* %i, align 4
br label %for.cond
for.cond: ; preds = %for.inc, %entry
%0 = load i32, i32* %i, align 4
%conv = sext i32 %0 to i64
%cmp = icmp ult i64 %conv, 64
br i1 %cmp, label %for.body, label %for.end
for.body: ; preds = %for.cond
%1 = ptrtoint i32** %A to i64
%2 = load i32, i32* %i, align 4
%sh_prom = zext i32 %2 to i64
%shl = shl i64 1, %sh_prom
%and = and i64 %1, %shl
%tobool = icmp ne i64 %and, 0
br i1 %tobool, label %if.then, label %if.end
if.then: ; preds = %for.body
%3 = load i32, i32* %i, align 4
%sh_prom2 = zext i32 %3 to i64
%shl3 = shl i64 1, %sh_prom2
%4 = load i64, i64* %RefCopy, align 8
%or = or i64 %4, %shl3
store i64 %or, i64* %RefCopy, align 8
br label %if.end
if.end: ; preds = %if.then, %for.body
br label %for.inc
for.inc: ; preds = %if.end
%5 = load i32, i32* %i, align 4
%inc = add nsw i32 %5, 1
store i32 %inc, i32* %i, align 4
br label %for.cond
for.end: ; preds = %for.cond
%6 = load i64, i64* %RefCopy, align 8
%7 = inttoptr i64 %6 to i32**
store i32** %7, i32*** %AliasA1, align 8
%8 = load i32**, i32*** %AliasA1, align 8
%9 = load i32*, i32** %8, align 8
store i32* %9, i32** %ShouldAliasA, align 8
ret void
}