[PATCH] D124889: [ValueTracking] Add support to deduce a PHI node being a power of 2 if each incoming value is a power of 2.
William Junda Huang via Phabricator via llvm-commits
llvm-commits at lists.llvm.org
Tue May 31 15:31:03 PDT 2022
huangjd updated this revision to Diff 433209.
huangjd added a comment.
[ValueTracking] Relaxed requirement of UseInstrInfo in power of 2
recurrece check
Repository:
rG LLVM Github Monorepo
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D124889/new/
https://reviews.llvm.org/D124889
Files:
llvm/lib/Analysis/ValueTracking.cpp
Index: llvm/lib/Analysis/ValueTracking.cpp
===================================================================
--- llvm/lib/Analysis/ValueTracking.cpp
+++ llvm/lib/Analysis/ValueTracking.cpp
@@ -2066,7 +2066,8 @@
switch (BO->getOpcode()) {
case Instruction::Mul:
// Power of two is closed under multiplication.
- return (OrZero || BO->hasNoUnsignedWrap() || BO->hasNoSignedWrap()) &&
+ return (OrZero || Q.IIQ.hasNoUnsignedWrap(BO) ||
+ Q.IIQ.hasNoSignedWrap(BO)) &&
isKnownToBeAPowerOfTwo(Step, OrZero, Depth, Q);
case Instruction::SDiv:
// Start value must not be signmask for signed division, so simply being a
@@ -2080,7 +2081,7 @@
// division, same for Shr.
return OrZero && isKnownToBeAPowerOfTwo(Step, false, Depth, Q);
case Instruction::Shl:
- return OrZero || BO->hasNoUnsignedWrap() || BO->hasNoSignedWrap();
+ return OrZero || Q.IIQ.hasNoUnsignedWrap(BO) || Q.IIQ.hasNoSignedWrap(BO);
case Instruction::AShr:
if (!match(Start, m_Power2()) || match(Start, m_SignMask()))
return false;
@@ -2189,7 +2190,7 @@
Query RecQ = Q;
// Check if it is an induction variable and always power of two.
- if (Q.IIQ.UseInstrInfo && isPowerOfTwoRecurrence(PN, OrZero, Depth, RecQ))
+ if (isPowerOfTwoRecurrence(PN, OrZero, Depth, RecQ))
return true;
// Recursively check all incoming values. Limit recursion to 2 levels, so
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