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llvm-mirror/test/Transforms/JumpThreading/indirectbr.ll
Chris Lattner eccec47f5c prevent jump threading from merging blocks when their address is
taken (and used!).  This prevents merging the blocks (invalidating
the block addresses) in a case like this:

#define _THIS_IP_  ({ __label__ __here; __here: (unsigned long)&&__here; })

void foo() {
  printf("%p\n", _THIS_IP_);
  printf("%p\n", _THIS_IP_);
  printf("%p\n", _THIS_IP_);
}

which fixes PR4151.

llvm-svn: 125829
2011-02-18 04:43:06 +00:00

95 lines
2.8 KiB
LLVM

; RUN: opt -S < %s -jump-threading | FileCheck %s
; Keep block addresses alive.
@addresses = constant [4 x i8*] [
i8* blockaddress(@test1, %L1), i8* blockaddress(@test1, %L2),
i8* blockaddress(@test2, %L1), i8* blockaddress(@test2, %L2)
]
declare void @bar()
declare void @baz()
; Check basic jump threading for indirectbr instructions.
; CHECK: void @test1
; CHECK: br i1 %tobool, label %L1, label %indirectgoto
; CHECK-NOT: if.else:
; CHECK: L1:
; CHECK: indirectbr i8* %address, [label %L1, label %L2]
define void @test1(i32 %i, i8* %address) nounwind {
entry:
%rem = srem i32 %i, 2
%tobool = icmp ne i32 %rem, 0
br i1 %tobool, label %indirectgoto, label %if.else
if.else: ; preds = %entry
br label %indirectgoto
L1: ; preds = %indirectgoto
call void @bar()
ret void
L2: ; preds = %indirectgoto
call void @baz()
ret void
indirectgoto: ; preds = %if.else, %entry
%indirect.goto.dest = phi i8* [ %address, %if.else ], [ blockaddress(@test1, %L1), %entry ]
indirectbr i8* %indirect.goto.dest, [label %L1, label %L2]
}
; Check constant folding of indirectbr
; CHECK: void @test2
; CHECK: entry:
; CHECK-NEXT: br label %L1
; CHECK: L1:
; CHECK-NEXT: call void @bar
; CHECK-NEXT: ret void
define void @test2() nounwind {
entry:
indirectbr i8* blockaddress(@test2, %L1), [label %L1, label %L2]
L1: ; preds = %indirectgoto
call void @bar()
ret void
L2: ; preds = %indirectgoto
call void @baz()
ret void
}
; PR4151
; Don't merge address-taken blocks.
@.str = private unnamed_addr constant [4 x i8] c"%p\0A\00"
; CHECK: @test3
; CHECK: __here:
; CHECK: blockaddress(@test3, %__here)
; CHECK: __here1:
; CHECK: blockaddress(@test3, %__here1)
; CHECK: __here3:
; CHECK: blockaddress(@test3, %__here3)
define void @test3() nounwind ssp noredzone {
entry:
br label %__here
__here: ; preds = %entry
%call = call i32 (...)* @printf(i8* getelementptr inbounds ([4 x i8]* @.str, i64 0, i64 0), i64 ptrtoint (i8* blockaddress(@test3, %__here) to i64)) nounwind noredzone
br label %__here1
__here1: ; preds = %__here
%call2 = call i32 (...)* @printf(i8* getelementptr inbounds ([4 x i8]* @.str, i64 0, i64 0), i64 ptrtoint (i8* blockaddress(@test3, %__here1) to i64)) nounwind noredzone
br label %__here3
__here3: ; preds = %__here1
%call4 = call i32 (...)* @printf(i8* getelementptr inbounds ([4 x i8]* @.str, i64 0, i64 0), i64 ptrtoint (i8* blockaddress(@test3, %__here3) to i64)) nounwind noredzone
ret void
}
declare i32 @printf(...) noredzone