[IR][PatternMatch] Introduce m_NegatedPower2() matcher

Summary:
It is a good idea to do as much matching inside of `match()` as possible.
If some checking is done afterwards, and we don't fold because of it,
chances are we may have missed some commutative pattern.

Reviewers: spatel, craig.topper, RKSimon

Reviewed By: spatel, RKSimon

Subscribers: llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D64038

llvm-svn: 367017
This commit is contained in:
Roman Lebedev 2019-07-25 13:34:24 +00:00
parent 784d5ec89a
commit 1191a4c398
2 changed files with 33 additions and 0 deletions

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@ -411,6 +411,18 @@ inline api_pred_ty<is_power2> m_Power2(const APInt *&V) {
return V;
}
struct is_negated_power2 {
bool isValue(const APInt &C) { return (-C).isPowerOf2(); }
};
/// Match a integer or vector negated power-of-2.
/// For vectors, this includes constants with undefined elements.
inline cst_pred_ty<is_negated_power2> m_NegatedPower2() {
return cst_pred_ty<is_negated_power2>();
}
inline api_pred_ty<is_negated_power2> m_NegatedPower2(const APInt *&V) {
return V;
}
struct is_power2_or_zero {
bool isValue(const APInt &C) { return !C || C.isPowerOf2(); }
};

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@ -7,6 +7,7 @@
//===----------------------------------------------------------------------===//
#include "llvm/IR/PatternMatch.h"
#include "llvm/ADT/APSInt.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/Analysis/ValueTracking.h"
#include "llvm/IR/BasicBlock.h"
@ -470,6 +471,26 @@ TEST_F(PatternMatchTest, Unless) {
EXPECT_FALSE(m_Unless(m_c_Add(m_Zero(), m_One())).match(X));
}
TEST_F(PatternMatchTest, Power2) {
Value *C128 = IRB.getInt32(128);
Value *CNeg128 = ConstantExpr::getNeg(cast<Constant>(C128));
EXPECT_TRUE(m_Power2().match(C128));
EXPECT_FALSE(m_Power2().match(CNeg128));
EXPECT_FALSE(m_NegatedPower2().match(C128));
EXPECT_TRUE(m_NegatedPower2().match(CNeg128));
Value *CIntMin = IRB.getInt64(APSInt::getSignedMinValue(64).getSExtValue());
Value *CNegIntMin = ConstantExpr::getNeg(cast<Constant>(CIntMin));
EXPECT_TRUE(m_Power2().match(CIntMin));
EXPECT_TRUE(m_Power2().match(CNegIntMin));
EXPECT_TRUE(m_NegatedPower2().match(CIntMin));
EXPECT_TRUE(m_NegatedPower2().match(CNegIntMin));
}
TEST_F(PatternMatchTest, CommutativeDeferredValue) {
Value *X = IRB.getInt32(1);
Value *Y = IRB.getInt32(2);