Matthias Braun e152c1527d InstCombine: Restrict computeKnownBits() on all Values to OptLevel > 2 ...

As part of r251146 InstCombine was extended to call computeKnownBits on
every value in the function to determine whether it happens to be
constant. This increases typical compiletime by 1-3% (5% in irgen+opt
time) in my measurements. On the other hand this case did not trigger
once in the whole llvm-testsuite.

This patch introduces the notion of ExpensiveCombines which are only
enabled for OptLevel > 2. I removed the check in InstructionSimplify as
that is called from various places where the OptLevel is not known but
given the rarity of the situation I think a check in InstCombine is
enough.

Differential Revision: http://reviews.llvm.org/D16835

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@263047 91177308-0d34-0410-b5e6-96231b3b80d8

2016-03-09 18:47:11 +00:00

..

llvm

InstCombine: Restrict computeKnownBits() on all Values to OptLevel > 2

2016-03-09 18:47:11 +00:00

llvm-c

Use lto_bool_t instead of a raw bool (fixup for r262977).

2016-03-09 04:05:28 +00:00