llvm/test/Transforms/SafeStack/phi.ll
Evgeniy Stepanov f268616d77 [safestack] Sink unsafe address computation to each use.
This is a fix for PR27844.
When replacing uses of unsafe allocas, emit the new location
immediately after each use. Without this, the pointer stays live from
the function entry to the last use, while it's usually cheaper to
recalculate.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@272969 91177308-0d34-0410-b5e6-96231b3b80d8
2016-06-16 22:34:04 +00:00

36 lines
1.1 KiB
LLVM

; RUN: opt -safe-stack -S -mtriple=i386-pc-linux-gnu < %s -o - | FileCheck %s
; RUN: opt -safe-stack -S -mtriple=x86_64-pc-linux-gnu < %s -o - | FileCheck %s
define void @f(i1 %d1, i1 %d2) safestack {
entry:
; CHECK-LABEL: define void @f(
; CHECK: %[[USP:.*]] = load i8*, i8** @__safestack_unsafe_stack_ptr
; CHECK-NEXT: getelementptr i8, i8* %[[USP]], i32 -16
; CHECK: br i1 %d1, label %[[BB0:.*]], label %[[BB1:.*]]
%a = alloca i32, align 8
%b = alloca i32, align 8
br i1 %d1, label %bb0, label %bb1
bb0:
; CHECK: [[BB0]]:
; CHECK: %[[Ai8:.*]] = getelementptr i8, i8* %unsafe_stack_ptr, i32
; CHECK: %[[AUNSAFE:.*]] = bitcast i8* %[[Ai8]] to i32*
; CHECK: br i1
br i1 %d2, label %bb2, label %bb2
bb1:
; CHECK: [[BB1]]:
; CHECK: %[[Bi8:.*]] = getelementptr i8, i8* %unsafe_stack_ptr, i32
; CHECK: %[[BUNSAFE:.*]] = bitcast i8* %[[Bi8]] to i32*
; CHECK: br label
br label %bb2
bb2:
; CHECK: phi i32* [ %[[AUNSAFE]], %[[BB0]] ], [ %[[AUNSAFE]], %[[BB0]] ], [ %[[BUNSAFE]], %[[BB1]] ]
%c = phi i32* [ %a, %bb0 ], [ %a, %bb0 ], [ %b, %bb1 ]
call void @capture(i32* %c)
ret void
}
declare void @capture(i32*)