llvm-mirror/test/Transforms/GVN/2011-06-01-NonLocalMemdepMiscompile.ll
Eli Friedman 884a7d08b1 When marking a block as being unanalyzable, use "Clobber" on the terminator instead of the first instruction in the block. This is a bit of a hack; "Clobber" isn't really the right marking in the first place. memdep doesn't really have any way of properly expressing "unanalyzable" at the moment. Using it on the terminator is much less ambiguous than using it on an arbitrary instruction, though.
In the given testcase, the "Clobber" was pointing to a load, and GVN was incorrectly assuming that meant that the "Clobber" load overlapped the load being analyzed (when they are actually unrelated).

The included testcase tests both this commit and r132434.

Part two of rdar://9429882.  (r132434 was mislabeled.)

llvm-svn: 132442
2011-06-02 00:08:52 +00:00

62 lines
1.6 KiB
LLVM

; RUN: opt < %s -basicaa -gvn -S | FileCheck %s
; This test is checking that (a) this doesn't crash, and (b) we don't
; conclude the value of %tmp17 is available in bb1.bb15_crit_edge.
; rdar://9429882
target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128-n8:16:32:64"
target triple = "x86_64-apple-macosx10.7.0"
define i1 @rb_intern() nounwind ssp {
; CHECK: @rb_intern
bb:
%tmp = alloca i8*, align 8
store i8* null, i8** %tmp, align 8
store i8 undef, i8* null, align 536870912
br label %bb1
bb1:
br i1 undef, label %bb3, label %bb15
; CHECK: bb1:
; CHECK: %tmp16 = phi i8* [ getelementptr (i8* null, i64 undef), %bb10 ], [ null, %bb ]
; CHECK: bb1.bb15_crit_edge:
; CHECK: %tmp17.pre = load i8* %tmp16, align 1
bb3:
call void @isalnum()
br i1 undef, label %bb10, label %bb5
bb5:
br i1 undef, label %bb10, label %bb6
bb6:
%tmp7 = load i8** %tmp, align 8
%tmp8 = load i8* %tmp7, align 1
%tmp9 = zext i8 %tmp8 to i64
br i1 undef, label %bb15, label %bb10
bb10:
%tmp11 = load i8** %tmp, align 8
%tmp12 = load i8* %tmp11, align 1
%tmp13 = zext i8 %tmp12 to i64
%tmp14 = getelementptr inbounds i8* null, i64 undef
store i8* %tmp14, i8** %tmp, align 8
br label %bb1
bb15:
%tmp16 = load i8** %tmp, align 8
%tmp17 = load i8* %tmp16, align 1
%tmp18 = icmp eq i8 %tmp17, 0
br label %bb19
; CHECK: bb15:
; CHECK: %tmp17 = phi i8 [ %tmp17.pre, %bb1.bb15_crit_edge ], [ %tmp8, %bb6 ]
bb19: ; preds = %bb15
ret i1 %tmp18
}
declare void @isalnum() nounwind inlinehint ssp