b7dfbb40a3
This patch improves SimplifyCFG to catch cases like:
if (a < b) {
if (a > b) <- known to be false
unreachable;
}
Phabricator Revision: http://reviews.llvm.org/D18905
llvm-svn: 266767
128 lines
2.7 KiB
LLVM
128 lines
2.7 KiB
LLVM
; RUN: opt -jump-threading -S < %s | FileCheck %s
|
|
|
|
declare void @side_effect(i32)
|
|
|
|
define void @test0(i32 %i, i32 %len) {
|
|
; CHECK-LABEL: @test0(
|
|
entry:
|
|
call void @side_effect(i32 0)
|
|
%i.inc = add nuw i32 %i, 1
|
|
%c0 = icmp ult i32 %i.inc, %len
|
|
br i1 %c0, label %left, label %right
|
|
|
|
left:
|
|
; CHECK: entry:
|
|
; CHECK: br i1 %c0, label %left0, label %right
|
|
|
|
; CHECK: left0:
|
|
; CHECK: call void @side_effect
|
|
; CHECK-NOT: br i1 %c1
|
|
; CHECK: call void @side_effect
|
|
call void @side_effect(i32 0)
|
|
%c1 = icmp ult i32 %i, %len
|
|
br i1 %c1, label %left0, label %right
|
|
|
|
left0:
|
|
call void @side_effect(i32 0)
|
|
ret void
|
|
|
|
right:
|
|
%t = phi i32 [ 1, %left ], [ 2, %entry ]
|
|
call void @side_effect(i32 %t)
|
|
ret void
|
|
}
|
|
|
|
define void @test1(i32 %i, i32 %len) {
|
|
; CHECK-LABEL: @test1(
|
|
entry:
|
|
call void @side_effect(i32 0)
|
|
%i.inc = add nsw i32 %i, 1
|
|
%c0 = icmp slt i32 %i.inc, %len
|
|
br i1 %c0, label %left, label %right
|
|
|
|
left:
|
|
; CHECK: entry:
|
|
; CHECK: br i1 %c0, label %left0, label %right
|
|
|
|
; CHECK: left0:
|
|
; CHECK: call void @side_effect
|
|
; CHECK-NOT: br i1 %c1
|
|
; CHECK: call void @side_effect
|
|
call void @side_effect(i32 0)
|
|
%c1 = icmp slt i32 %i, %len
|
|
br i1 %c1, label %left0, label %right
|
|
|
|
left0:
|
|
call void @side_effect(i32 0)
|
|
ret void
|
|
|
|
right:
|
|
%t = phi i32 [ 1, %left ], [ 2, %entry ]
|
|
call void @side_effect(i32 %t)
|
|
ret void
|
|
}
|
|
|
|
define void @test2(i32 %i, i32 %len, i1* %c.ptr) {
|
|
; CHECK-LABEL: @test2(
|
|
|
|
; CHECK: entry:
|
|
; CHECK: br i1 %c0, label %cont, label %right
|
|
; CHECK: cont:
|
|
; CHECK: br i1 %c, label %left0, label %right
|
|
; CHECK: left0:
|
|
; CHECK: call void @side_effect(i32 0)
|
|
; CHECK: call void @side_effect(i32 0)
|
|
entry:
|
|
call void @side_effect(i32 0)
|
|
%i.inc = add nsw i32 %i, 1
|
|
%c0 = icmp slt i32 %i.inc, %len
|
|
br i1 %c0, label %cont, label %right
|
|
|
|
cont:
|
|
%c = load i1, i1* %c.ptr
|
|
br i1 %c, label %left, label %right
|
|
|
|
left:
|
|
call void @side_effect(i32 0)
|
|
%c1 = icmp slt i32 %i, %len
|
|
br i1 %c1, label %left0, label %right
|
|
|
|
left0:
|
|
call void @side_effect(i32 0)
|
|
ret void
|
|
|
|
right:
|
|
%t = phi i32 [ 1, %left ], [ 2, %entry ], [ 3, %cont ]
|
|
call void @side_effect(i32 %t)
|
|
ret void
|
|
}
|
|
|
|
; A s<= B implies A s> B is false.
|
|
; CHECK-LABEL: @test3(
|
|
; CHECK: entry:
|
|
; CHECK: br i1 %cmp, label %if.end, label %if.end3
|
|
; CHECK-NOT: br i1 %cmp1, label %if.then2, label %if.end
|
|
; CHECK-NOT: call void @side_effect(i32 0)
|
|
; CHECK: br label %if.end3
|
|
; CHECK: ret void
|
|
|
|
define void @test3(i32 %a, i32 %b) {
|
|
entry:
|
|
%cmp = icmp sle i32 %a, %b
|
|
br i1 %cmp, label %if.then, label %if.end3
|
|
|
|
if.then:
|
|
%cmp1 = icmp sgt i32 %a, %b
|
|
br i1 %cmp1, label %if.then2, label %if.end
|
|
|
|
if.then2:
|
|
call void @side_effect(i32 0)
|
|
br label %if.end
|
|
|
|
if.end:
|
|
br label %if.end3
|
|
|
|
if.end3:
|
|
ret void
|
|
}
|