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Remove a test that was ported from the old llvm-gcc frontend test suite.

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This test is pretty awesome. It is claiming to test devirtualization.
However, the code in question is not in fact devirtualized by LLVM. If
you take the original C++ test case and run it through Clang at -O3 we
fail to devirtualize it completely. It also isn't a sufficiently focused
test case.

The *reason* we fail to devirtualize it isn't because of any missing
instcombine though. Instead, it is because we fail to emit an available
externally vtable and thus the vtable is just an external and completely
opaque. If I cause the vtable to be emitted, we successfully
devirtualize things.

Anyways, I'm just removing it because it is providing negative value at
this point: it isn't representative of the output of Clang really, LLVM
isn't doing the transform it claims to be testing, LLVM's failure to do
the transform isn't actually an LLVM bug at all and we shouldn't be
testing for it here, and finally the test is written in such a way that
it will trivially pass even when the point of the test is failing.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@220137 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Chandler Carruth 2014-10-18 06:36:18 +00:00
parent 5357e3ae1b
commit a45d0c8bd1
1 changed files with 0 additions and 39 deletions
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39
test/Transforms/InstCombine/devirt.ll
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@ -1,39 +0,0 @@
; RUN: opt -instcombine -S < %s | FileCheck %s
; CHECK-NOT: getelementptr
; CHECK-NOT: ptrtoint
; CHECK: bitcast i8*
%struct.S = type { i32 (...)** }
@_ZL1p = internal constant { i64, i64 } { i64 1, i64 0 }, align 8
define void @_Z1g1S(%struct.S* %s) nounwind {
entry:
%tmp = load { i64, i64 }* @_ZL1p, align 8
%memptr.adj = extractvalue { i64, i64 } %tmp, 1
%0 = bitcast %struct.S* %s to i8*
%1 = getelementptr inbounds i8* %0, i64 %memptr.adj
%this.adjusted = bitcast i8* %1 to %struct.S*
%memptr.ptr = extractvalue { i64, i64 } %tmp, 0
%2 = and i64 %memptr.ptr, 1
%memptr.isvirtual = icmp ne i64 %2, 0
br i1 %memptr.isvirtual, label %memptr.virtual, label %memptr.nonvirtual
memptr.virtual: ; preds = %entry
%3 = bitcast %struct.S* %this.adjusted to i8**
%memptr.vtable = load i8** %3
%4 = sub i64 %memptr.ptr, 1
%5 = getelementptr i8* %memptr.vtable, i64 %4
%6 = bitcast i8* %5 to void (%struct.S*)**
%memptr.virtualfn = load void (%struct.S*)** %6
br label %memptr.end
memptr.nonvirtual: ; preds = %entry
%memptr.nonvirtualfn = inttoptr i64 %memptr.ptr to void (%struct.S*)*
br label %memptr.end
memptr.end: ; preds = %memptr.nonvirtual, %memptr.virtual
%7 = phi void (%struct.S*)* [ %memptr.virtualfn, %memptr.virtual ], [ %memptr.nonvirtualfn, %memptr.nonvirtual ]
call void %7(%struct.S* %this.adjusted)
ret void
}