llvm-6502/test/Transforms/SimplifyCFG/phi-undef-loadstore.ll
Benjamin Kramer 1e21db6e83 SimplifyCFG: Enhance the "remove CFG edge that leads to null pointer dereference" optimization to also handle instructions with multiple uses.
We conservatively only check the first use to avoid walking long use chains.
This catches the common case of having both a load and a store to a pointer
supplied by a PHI node.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@165232 91177308-0d34-0410-b5e6-96231b3b80d8
2012-10-04 16:11:49 +00:00

116 lines
3.5 KiB
LLVM

; RUN: opt -simplifycfg -S < %s | FileCheck %s
declare void @bar() nounwind
define i32 @test1(i32* %a, i32 %b, i32* %c, i32 %d) nounwind {
entry:
%tobool = icmp eq i32 %b, 0
br i1 %tobool, label %if.else, label %if.then
if.then: ; preds = %entry
tail call void @bar() nounwind
br label %if.end7
if.else: ; preds = %entry
%tobool3 = icmp eq i32 %d, 0
br i1 %tobool3, label %if.end7, label %if.then4
if.then4: ; preds = %if.else
tail call void @bar() nounwind
br label %if.end7
if.end7: ; preds = %if.else, %if.then4, %if.then
%x.0 = phi i32* [ %a, %if.then ], [ %c, %if.then4 ], [ null, %if.else ]
%tmp9 = load i32* %x.0
ret i32 %tmp9
; CHECK: @test1
; CHECK: if.else:
; CHECK: br label %if.end7
; CHECK: phi i32* [ %a, %if.then ], [ %c, %if.else ]
}
define i32 @test2(i32* %a, i32 %b, i32* %c, i32 %d) nounwind {
entry:
%tobool = icmp eq i32 %b, 0
br i1 %tobool, label %if.else, label %if.then
if.then: ; preds = %entry
tail call void @bar() nounwind
br label %if.end7
if.else: ; preds = %entry
%tobool3 = icmp eq i32 %d, 0
br i1 %tobool3, label %if.end7, label %if.then4
if.then4: ; preds = %if.else
tail call void @bar() nounwind
br label %if.end7
if.end7: ; preds = %if.else, %if.then4, %if.then
%x.0 = phi i32* [ %a, %if.then ], [ null, %if.then4 ], [ null, %if.else ]
%tmp9 = load i32* %x.0
ret i32 %tmp9
; CHECK: @test2
; CHECK: if.else:
; CHECK: unreachable
; CHECK-NOT: phi
}
define i32 @test3(i32* %a, i32 %b, i32* %c, i32 %d) nounwind {
entry:
%tobool = icmp eq i32 %b, 0
br i1 %tobool, label %if.else, label %if.then
if.then: ; preds = %entry
tail call void @bar() nounwind
br label %if.end7
if.else: ; preds = %entry
%tobool3 = icmp eq i32 %d, 0
br i1 %tobool3, label %if.end7, label %if.then4
if.then4: ; preds = %if.else
tail call void @bar() nounwind
br label %if.end7
if.end7: ; preds = %if.else, %if.then4, %if.then
%x.0 = phi i32* [ %a, %if.then ], [ null, %if.then4 ], [ null, %if.else ]
tail call void @bar() nounwind
%tmp9 = load i32* %x.0
ret i32 %tmp9
; CHECK: @test3
; CHECK: if.end7:
; CHECK: phi i32* [ %a, %if.then ], [ null, %if.then4 ], [ null, %if.else ]
}
define i32 @test4(i32* %a, i32 %b, i32* %c, i32 %d) nounwind {
entry:
%tobool = icmp eq i32 %b, 0
br i1 %tobool, label %if.else, label %if.then
if.then: ; preds = %entry
tail call void @bar() nounwind
br label %if.end7
if.else: ; preds = %entry
%tobool3 = icmp eq i32 %d, 0
br i1 %tobool3, label %if.end7, label %if.then4
if.then4: ; preds = %if.else
tail call void @bar() nounwind
br label %if.end7
if.end7: ; preds = %if.else, %if.then4, %if.then
%x.0 = phi i32* [ %a, %if.then ], [ null, %if.then4 ], [ null, %if.else ]
%gep = getelementptr i32* %x.0, i32 10
%tmp9 = load i32* %gep
%tmp10 = or i32 %tmp9, 1
store i32 %tmp10, i32* %gep
ret i32 %tmp9
; CHECK: @test4
; CHECK-NOT: phi
}