11 Commits

Author SHA1 Message Date
Mehdi Amini
9ff867f98c [NFC] Header cleanup
Removed some unused headers, replaced some headers with forward class declarations.

Found using simple scripts like this one:
clear && ack --cpp -l '#include "llvm/ADT/IndexedMap.h"' | xargs grep -L 'IndexedMap[<]' | xargs grep -n --color=auto 'IndexedMap'

Patch by Eugene Kosov <claprix@yandex.ru>

Differential Revision: http://reviews.llvm.org/D19219

From: Mehdi Amini <mehdi.amini@apple.com>
llvm-svn: 266595
2016-04-18 09:17:29 +00:00
James Molloy
08b726e6d4 [DemandedBits] Revert r249687 due to PR26071
This regresses a test in LoopVectorize, so I'll need to go away and think about how to solve this in a way that isn't broken.

From the writeup in PR26071:

What's happening is that ComputeKnownZeroes is telling us that all bits except the LSB are zero. We're then deciding that only the LSB needs to be demanded from the icmp's inputs.

This is where we're wrong - we're assuming that after simplification the bits that were known zero will continue to be known zero. But they're not - during trivialization the upper bits get changed (because an XOR isn't shrunk), so the icmp fails.

The fault is in demandedbits - its contract does clearly state that a non-demanded bit may either be zero or one.

llvm-svn: 259649
2016-02-03 15:05:06 +00:00
Benjamin Kramer
cc4037f846 Make some headers self-contained, remove unused includes that violate layering.
llvm-svn: 258937
2016-01-27 16:05:37 +00:00
James Molloy
fe66a6200d [DemandedBits] Fix computation of demanded bits for ICmps
The computation of ICmp demanded bits is independent of the individual operand being evaluated. We simply return a mask consisting of the minimum leading zeroes of both operands.

We were incorrectly passing "I" to ComputeKnownBits - this should be "UserI->getOperand(0)". In cases where we were evaluating the 1th operand, we were taking the minimum leading zeroes of it and itself.

This should fix PR26266.

llvm-svn: 258690
2016-01-25 14:49:36 +00:00
James Molloy
2ccf761faa Compute demanded bits for icmp instructions
Instead of bailing out when we see an icmp, we can instead at least
say that if the upper bits of both operands are known zero, they are
not demanded. This doesn't help with signed comparisons, but it's at
least better than bailing out.

llvm-svn: 249687
2015-10-08 12:40:06 +00:00
James Molloy
5da32b5e20 Treat Mul just like Add and Subtract
Like adds and subtracts, muls ripple only to the left so we can use
the same logic.

While we're here, add a print method to DemandedBits so it can be used
with -analyze, which we'll use in the testcase.

llvm-svn: 249686
2015-10-08 12:39:59 +00:00
James Molloy
496f624786 Make demanded bits lazy
The algorithm itself is still eager, but it doesn't get run until a
query function is called. This greatly reduces the compile-time impact
of requiring DemandedBits when at runtime it is not often used.

NFCI.

llvm-svn: 249685
2015-10-08 12:39:50 +00:00
NAKAMURA Takumi
dd4e00ed1e Untabify.
llvm-svn: 248264
2015-09-22 11:15:07 +00:00
NAKAMURA Takumi
a6e5b048c7 Reformat comment lines.
llvm-svn: 248262
2015-09-22 11:14:12 +00:00
NAKAMURA Takumi
8c11e8767b Reformat.
llvm-svn: 248261
2015-09-22 11:13:55 +00:00
James Molloy
025f427f26 Separate out BDCE's analysis into a separate DemandedBits analysis.
This allows other areas of the compiler to use BDCE's bit-tracking.
NFCI.

llvm-svn: 245039
2015-08-14 11:09:09 +00:00