search for: icmp_n

Hello, In one of the loop transformations I am developing, I need to convert eq and neq loop latch condition into less than or greater than depending on the control flow. The problem is that CmpInst::ICMP_EQ and CmpInst::ICMP_NE are neither signed nor unsigned in LLVM. Also, I did not find a way to find out if the integer operands of the CmpInst are signed or unsigned. Apparently, LLVM does not distinguish in its type system between signed and unsigned variables. So, I am not able to generate the appropriate signed or uns...

...<Instruction>(LHSPtr)) - if (Argument *RHSArg = dyn_cast<Argument>(RHSPtr)) - if (LHSInst->getParent()->getParent() == RHSArg->getParent() && - Pred == CmpInst::ICMP_EQ) - return ConstantInt::get(ITy, false); + case ICmpInst::ICMP_NE: + return ConstantInt::get(ITy, true); + } } - - // Assume that the constant null is on the right. - if (llvm::isKnownNonNull(LHSPtr) && isa<ConstantPointerNull>(RHSPtr)) { - if (Pred == CmpInst::ICMP_EQ) + if (LHSPtr == RHSPtr) { + switch (Predica...

On Wed, Dec 12, 2012 at 1:26 PM, Joerg Sonnenberger <joerg at britannica.bec.de> wrote: > On Wed, Dec 12, 2012 at 11:01:01AM -0800, Dan Gohman wrote: >> > Is that >> > assumption violated if I explicitly cast away const and pass the result >> > to a function with NoAlias argument? >> >> Not immediately, no. It means that you can't access the

On Wed, Dec 12, 2012 at 11:01:01AM -0800, Dan Gohman wrote: > > Is that > > assumption violated if I explicitly cast away const and pass the result > > to a function with NoAlias argument? > > Not immediately, no. It means that you can't access the constant > pointer's pointee directly within the noalias argument's scope. Access > to that object must go

...on containing a "=", such as: void scop_func(long A[], long n) { long i; for (i = 1; i<= n; i++) A[i] = 1; } after have a look at the code that computing the back-edge taken count, i found that ScalarEvolution could only compute back-edge taken count if the exit condition is ICMP_NE/ICMP_EQ/ICMP_SLT/ICMP_SGT/ICMP_ULT/ICMP_UGT (ignoring "ComputeBackedgeTakenCountExhaustively"), and the function "SimplifyICmpOperands" will try to convert other conditions to the conditions listed above, by doing something like "i <= n" to "i < n+1",...

Sorry, I'm a bit confused by your reply. I think part of my problem is I can only think of this in terms of Passes. For instance, my pass looks for assignments and tries to use the same pointer operand, before the assignment it finds. Like this: new ICmpInst(*block, CmpInst::ICMP_NE, shadow, store->getPointerOperand(), "Shadow check"); So I'm not sure how alloca could help me, seems like it wouldn't be a valid Value * for me to pass in at that point. Am I missing something? Thank you On Mon, Sep 19, 2011 at 2:02 PM, John Criswell <criswell at illino...

...a bit confused by your reply. I think part of my problem is > I can only think of this in terms of Passes. > > For instance, my pass looks for assignments and tries to use the same > pointer operand, before the assignment it finds. Like this: > new ICmpInst(*block, CmpInst::ICMP_NE, shadow, > store->getPointerOperand(), "Shadow check"); Can you clarify what you mean by "an assignment?" Do you mean an LLVM store instruction, or do you mean an SSA assignment of an LLVM virtual register? > > So I'm not sure how alloca could help me, seems...

...+ FCMP_UNE = 14, ///< 1 1 1 0 True if unordered or not equal + FCMP_TRUE = 15, ///< 1 1 1 1 Always true (always folded) FIRST_FCMP_PREDICATE = FCMP_FALSE, LAST_FCMP_PREDICATE = FCMP_TRUE, BAD_FCMP_PREDICATE = FCMP_TRUE + 1, - ICMP_EQ = 32, /// equal - ICMP_NE = 33, /// not equal - ICMP_UGT = 34, /// unsigned greater than - ICMP_UGE = 35, /// unsigned greater or equal - ICMP_ULT = 36, /// unsigned less than - ICMP_ULE = 37, /// unsigned less or equal - ICMP_SGT = 38, /// signed greater than - ICMP_SGE = 39, /// si...

...rg = A->hasByValAttr(); + } - // Assume that the constant null is on the right. - if (llvm::isKnownNonNull(LHSPtr) && isa<ConstantPointerNull>(RHSPtr)) { - if (Pred == CmpInst::ICMP_EQ) - return ConstantInt::get(ITy, false); - else if (Pred == CmpInst::ICMP_NE) - return ConstantInt::get(ITy, true); - } - } else if (Argument *LHSArg = dyn_cast<Argument>(LHSPtr)) { - RHSPtr = RHSPtr->stripInBoundsOffsets(); - // An alloca can't be equal to an argument unless they come from separate - // functions via inlining. - if (All...

...> void scop_func(long A[], long n) { > long i; > > for (i = 1; i<= n; i++) > A[i] = 1; > } > > after have a look at the code that computing the back-edge taken count, i found that ScalarEvolution could only compute back-edge taken count if the exit condition is ICMP_NE/ICMP_EQ/ICMP_SLT/ICMP_SGT/ICMP_ULT/ICMP_UGT (ignoring "ComputeBackedgeTakenCountExhaustively"), and the function "SimplifyICmpOperands" will try to convert other conditions to the conditions listed above, by doing something like "i <= n" to "i < n+1",...

...inst_iterator i, GlobalVariable *shadow, Value *val) { /* Split old Block */ BasicBlock *bb = i->getParent(); BasicBlock *bb_after = i->getParent()->splitBasicBlock(&*i); bb->getTerminator()->eraseFromParent(); /* Test */ ICmpInst *test = new ICmpInst(*bb, CmpInst::ICMP_NE, shadow, val, "Shadow check"); /* Fail */ BasicBlock *trueBlock = BasicBlock::Create(M.getContext(), "Shadow Check FAIL", &F); CallInst::Create(qv_segFault, "", trueBlock); BranchInst::Create(bb_after, trueBlock); /* Profit */ BranchInst::Create(...

...*Con; + if (!((Con = dyn_cast<ConstantInt>(LHS)) || (Con = dyn_cast<ConstantInt>(RHS)))) + return nullptr; + uint64_t con_val = Con->getZExtValue(); + + if (RHS == CI) + IC->swapOperands(); + + switch (IC->getPredicate()) { + case ICmpInst::ICMP_EQ: + case ICmpInst::ICMP_NE: + case ICmpInst::ICMP_UGT: + case ICmpInst::ICMP_UGE: + case ICmpInst::ICMP_ULE: + case ICmpInst::ICMP_SGT: + case ICmpInst::ICMP_SGE: + case ICmpInst::ICMP_SLE: + // XXX: check for wrapping + if (con_val == UINT64_MAX) + return nullptr; + return emitStrNLen(Src, ConstantInt::...

On 9/19/11 12:53 PM, ret val wrote: > Is there a easy way to copy a Value object, so it can be used in > multiple instructions without a dominance issue? A value object can be used multiple times with no problem. The dominance problem stems from the fact that the program must be in SSA form. When the program uses a value, it must have been defined dynamically for all possible executions

Is there a easy way to copy a Value object, so it can be used in multiple instructions without a dominance issue?

I was trying to build the Linux kernel with clang and observed a crash due to incorrect loop optimization: drivers/base/firmware_class.c extern struct builtin_fw __start_builtin_fw[]; extern struct builtin_fw __end_builtin_fw[]; static bool fw_get_builtin_firmware(struct firmware *fw, const char *name) { struct builtin_fw *b_fw; for (b_fw = __start_builtin_fw; b_fw != __end_builtin_fw;