llvm-project/llvm/test/Transforms/CorrelatedValuePropagation
Hal Finkel cb9f78e1c3 Make processing @llvm.assume more efficient by using operand bundles
There was an efficiency problem with how we processed @llvm.assume in
ValueTracking (and other places). The AssumptionCache tracked all of the
assumptions in a given function. In order to find assumptions relevant to
computing known bits, etc. we searched every assumption in the function. For
ValueTracking, that means that we did O(#assumes * #values) work in InstCombine
and other passes (with a constant factor that can be quite large because we'd
repeat this search at every level of recursion of the analysis).

Several of us discussed this situation at the last developers' meeting, and
this implements the discussed solution: Make the values that an assume might
affect operands of the assume itself. To avoid exposing this detail to
frontends and passes that need not worry about it, I've used the new
operand-bundle feature to add these extra call "operands" in a way that does
not affect the intrinsic's signature. I think this solution is relatively
clean. InstCombine adds these extra operands based on what ValueTracking, LVI,
etc. will need and then those passes need only search the users of the values
under consideration. This should fix the computational-complexity problem.

At this point, no passes depend on the AssumptionCache, and so I'll remove
that as a follow-up change.

Differential Revision: https://reviews.llvm.org/D27259

llvm-svn: 289755
2016-12-15 02:53:42 +00:00
..
2010-09-02-Trunc.ll
2010-09-26-MergeConstantRange.ll
add.ll [CVP] Remove use of removed flag (-cvp-dont-process-adds) from the test 2016-11-29 16:43:30 +00:00
alloca.ll llvm/test/Transforms/CorrelatedValuePropagation/alloca.ll REQUIRES +Asserts. 2016-09-15 09:45:31 +00:00
ashr.ll [CVP] Convert an AShr to a LShr if 1st operand is known to be nonnegative. 2016-10-12 13:41:38 +00:00
basic.ll [LVI] Reduce compile time by lazily scanning blocks if needed 2016-04-27 00:30:55 +00:00
conflict.ll Make processing @llvm.assume more efficient by using operand bundles 2016-12-15 02:53:42 +00:00
crash.ll [LVI] Fix potential memory corruption in getValueFromCondition 2016-08-12 15:08:15 +00:00
guards.ll [LVI] Fix a bug with a guard being the very first instruction in a BB not taken into account 2016-10-21 15:02:21 +00:00
icmp.ll [PM] Port CorrelatedValuePropagation 2016-07-06 23:26:29 +00:00
non-null.ll
range.ll [LVI] Take range metadata into account while calculating icmp condition constraints 2016-08-12 10:14:11 +00:00
sdiv.ll Remove extra whitespace. NFC. 2016-05-02 16:45:00 +00:00
select.ll [LVI] Improve select handling to use condition 2016-02-12 00:09:18 +00:00
srem.ll This converts a signed remainder instruction to unsigned remainder, which 2016-07-14 12:23:48 +00:00