Revert r237539: "Reapply r237520 with another fix for infinite looping"

This caused PR23583.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@237739 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Hans Wennborg
2015-05-19 23:06:30 +00:00
parent 486f97bf19
commit c0f6113287
6 changed files with 7 additions and 162 deletions
@@ -3970,19 +3970,6 @@ Instruction *InstCombiner::visitFCmpInst(FCmpInst &I) {
}
}
// Test if the FCmpInst instruction is used exclusively by a select as
// part of a minimum or maximum operation. If so, refrain from doing
// any other folding. This helps out other analyses which understand
// non-obfuscated minimum and maximum idioms, such as ScalarEvolution
// and CodeGen. And in this case, at least one of the comparison
// operands has at least one user besides the compare (the select),
// which would often largely negate the benefit of folding anyway.
if (I.hasOneUse())
if (SelectInst *SI = dyn_cast<SelectInst>(*I.user_begin()))
if ((SI->getOperand(1) == Op0 && SI->getOperand(2) == Op1) ||
(SI->getOperand(2) == Op0 && SI->getOperand(1) == Op1))
return nullptr;
// Handle fcmp with constant RHS
if (Constant *RHSC = dyn_cast<Constant>(Op1)) {
if (Instruction *LHSI = dyn_cast<Instruction>(Op0))