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The method of doing the matching with a 'select' instruction was wrong. The

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original code was matching like this:

	if (match(A, m_Not(m_Value(B))))

B was already matched as a 'select' instruction. However, this isn't matching
what we think it's matching. It would match B as a 'Value', so basically
anything would match to it. In this case, a Constant matched. B was replaced
with a constant representation. And then the wrong value would be used in the
SelectInst::Create statement, causing a crash.

After thinking on this for a moment, and after Nick L. told me how the pattern
matching stuff was supposed to work, the solution was to match NOT an m_Value,
but an m_Select.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@58946 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Bill Wendling 2008-11-09 23:17:42 +00:00
parent 47ed475dec
commit 1fb43c32ed
2 changed files with 56 additions and 32 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

71
lib/Transforms/Scalar/InstructionCombining.cpp
View File

@ -4352,55 +4352,62 @@ Instruction *InstCombiner::visitOr(BinaryOperator &I) {
}
}
#define SELECT_MATCH(Val) \
m_Select(m_Value(Val), m_ConstantInt(0), m_ConstantInt(-1))
#define GET_SELECT_COND(Val) \
cast<User>(Val)->getOperand(0)
// (A & (C0?-1:0)) | (B & ~(C0?-1:0)) -> C0 ? A : B, and commuted variants
if (match(A, m_Select(m_Value(), m_ConstantInt(-1), m_ConstantInt(0)))) {
if (match(D, m_Not(m_Value(A))))
return SelectInst::Create(cast<User>(A)->getOperand(0), C, B);
if (match(B, m_Not(m_Value(A))))
return SelectInst::Create(cast<User>(A)->getOperand(0), C, D);
if (match(D, m_Not(SELECT_MATCH(A))))
return SelectInst::Create(GET_SELECT_COND(D), C, B);
if (match(B, m_Not(SELECT_MATCH(A))))
return SelectInst::Create(GET_SELECT_COND(B), C, D);
}
if (match(B, m_Select(m_Value(), m_ConstantInt(-1), m_ConstantInt(0)))) {
if (match(C, m_Not(m_Value(B))))
return SelectInst::Create(cast<User>(B)->getOperand(0), A, D);
if (match(A, m_Not(m_Value(B))))
return SelectInst::Create(cast<User>(B)->getOperand(0), C, D);
if (match(C, m_Not(SELECT_MATCH(B))))
return SelectInst::Create(GET_SELECT_COND(C), A, D);
if (match(A, m_Not(SELECT_MATCH(B))))
return SelectInst::Create(GET_SELECT_COND(A), C, D);
}
if (match(C, m_Select(m_Value(), m_ConstantInt(-1), m_ConstantInt(0)))) {
if (match(D, m_Not(m_Value(C))))
return SelectInst::Create(cast<User>(C)->getOperand(0), A, B);
if (match(B, m_Not(m_Value(C))))
return SelectInst::Create(cast<User>(C)->getOperand(0), A, D);
if (match(D, m_Not(SELECT_MATCH(C))))
return SelectInst::Create(GET_SELECT_COND(D), A, B);
if (match(B, m_Not(SELECT_MATCH(C))))
return SelectInst::Create(GET_SELECT_COND(B), A, D);
}
if (match(D, m_Select(m_Value(), m_ConstantInt(-1), m_ConstantInt(0)))) {
if (match(C, m_Not(m_Value(D))))
return SelectInst::Create(cast<User>(D)->getOperand(0), A, B);
if (match(A, m_Not(m_Value(D))))
return SelectInst::Create(cast<User>(D)->getOperand(0), C, B);
if (match(C, m_Not(SELECT_MATCH(D))))
return SelectInst::Create(GET_SELECT_COND(C), A, B);
if (match(A, m_Not(SELECT_MATCH(D))))
return SelectInst::Create(GET_SELECT_COND(A), C, B);
}
if (match(A, m_Select(m_Value(), m_ConstantInt(0), m_ConstantInt(-1)))) {
if (match(D, m_Not(m_Value(A))))
return SelectInst::Create(cast<User>(A)->getOperand(0), B, C);
if (match(B, m_Not(m_Value(A))))
return SelectInst::Create(cast<User>(A)->getOperand(0), D, C);
if (match(D, m_Not(SELECT_MATCH(A))))
return SelectInst::Create(GET_SELECT_COND(D), B, C);
if (match(B, m_Not(SELECT_MATCH(A))))
return SelectInst::Create(GET_SELECT_COND(B), D, C);
}
if (match(B, m_Select(m_Value(), m_ConstantInt(0), m_ConstantInt(-1)))) {
if (match(C, m_Not(m_Value(B))))
return SelectInst::Create(cast<User>(B)->getOperand(0), D, A);
if (match(A, m_Not(m_Value(B))))
return SelectInst::Create(cast<User>(B)->getOperand(0), D, C);
if (match(C, m_Not(SELECT_MATCH(B))))
return SelectInst::Create(GET_SELECT_COND(C), D, A);
if (match(A, m_Not(SELECT_MATCH(B))))
return SelectInst::Create(GET_SELECT_COND(A), D, C);
}
if (match(C, m_Select(m_Value(), m_ConstantInt(0), m_ConstantInt(-1)))) {
if (match(D, m_Not(m_Value(C))))
return SelectInst::Create(cast<User>(C)->getOperand(0), B, A);
if (match(B, m_Not(m_Value(C))))
return SelectInst::Create(cast<User>(C)->getOperand(0), D, A);
if (match(D, m_Not(SELECT_MATCH(C))))
return SelectInst::Create(GET_SELECT_COND(D), B, A);
if (match(B, m_Not(SELECT_MATCH(C))))
return SelectInst::Create(GET_SELECT_COND(B), D, A);
}
if (match(D, m_Select(m_Value(), m_ConstantInt(0), m_ConstantInt(-1)))) {
if (match(C, m_Not(m_Value(D))))
return SelectInst::Create(cast<User>(D)->getOperand(0), B, A);
if (match(A, m_Not(m_Value(D))))
return SelectInst::Create(cast<User>(D)->getOperand(0), B, C);
if (match(C, m_Not(SELECT_MATCH(D))))
return SelectInst::Create(GET_SELECT_COND(C), B, A);
if (match(A, m_Not(SELECT_MATCH(D))))
return SelectInst::Create(GET_SELECT_COND(A), B, C);
}
#undef SELECT_MATCH
#undef GET_SELECT_COND
}
// (X >> Z) | (Y >> Z) -> (X|Y) >> Z for all shifts.

17
test/FrontendC/2008-11-08-InstCombineSelect.c Normal file
View File

@ -0,0 +1,17 @@
// RUN: %llvmgcc %s -S -emit-llvm -O2 -o -
// PR3028
int g_187;
int g_204;
int g_434;
int func_89 (void)
{
return 1;
}
void func_20 (int p_22)
{
if (1 & p_22 | g_204 & (1 < g_187) - func_89 ())
g_434 = 1;
}