[llvm] [llvm] Add KnownBits implementations for avgFloor and avgCeil (PR #86445)
Nhat Nguyen via llvm-commits
llvm-commits at lists.llvm.org
Sun Mar 24 10:55:55 PDT 2024
https://github.com/changkhothuychung created https://github.com/llvm/llvm-project/pull/86445
This PR is to address the issue #84640
>From e447f4c15ced2880f520d636ffc239d1368032b7 Mon Sep 17 00:00:00 2001
From: changkhothuychung <nhat7203 at gmail.com>
Date: Sun, 24 Mar 2024 13:54:21 -0400
Subject: [PATCH] initial attempt
---
llvm/lib/Support/KnownBits.cpp | 40 ++++++++++++++++++++++++++++++++++
1 file changed, 40 insertions(+)
diff --git a/llvm/lib/Support/KnownBits.cpp b/llvm/lib/Support/KnownBits.cpp
index d72355dab6f1d3..07c7ad0882387a 100644
--- a/llvm/lib/Support/KnownBits.cpp
+++ b/llvm/lib/Support/KnownBits.cpp
@@ -762,6 +762,46 @@ KnownBits KnownBits::usub_sat(const KnownBits &LHS, const KnownBits &RHS) {
return computeForSatAddSub(/*Add*/ false, /*Signed*/ false, LHS, RHS);
}
+KnownBits KnownBits::avgFloorS(const KnownBits &LHS, const KnownBits &RHS) {
+ // (C1 & C2) + (C1 ^ C2).ashr(1)
+ KnownBits andResult = LHS & RHS;
+ KnownBits xorResult = LHS ^ RHS;
+ xorResult.Zero.ashrInPlace(1);
+ xorResult.One.ashrInPlace(1);
+ return computeForSatAddSub(/*Add*/ true, /*Signed*/ true, andResult,
+ xorResult);
+}
+
+KnownBits KnownBits::avgFloorU(const KnownBits &LHS, const KnownBits &RHS) {
+ // (C1 & C2) + (C1 ^ C2).lshr(1)
+ KnownBits andResult = LHS & RHS;
+ KnownBits xorResult = LHS ^ RHS;
+ xorResult.Zero.lshrInPlace(1);
+ xorResult.One.lshrInPlace(1);
+ return computeForSatAddSub(/*Add*/ true, /*Signed*/ false, andResult,
+ xorResult);
+}
+
+KnownBits KnownBits::avgCeilS(const KnownBits &LHS, const KnownBits &RHS) {
+ // (C1 | C2) - (C1 ^ C2).ashr(1)
+ KnownBits andResult = LHS & RHS;
+ KnownBits xorResult = LHS ^ RHS;
+ xorResult.Zero.ashrInPlace(1);
+ xorResult.One.ashrInPlace(1);
+ return computeForSatAddSub(/*Add*/ false, /*Signed*/ true, andResult,
+ xorResult);
+}
+
+KnownBits KnownBits::avgCeilU(const KnownBits &LHS, const KnownBits &RHS) {
+ // (C1 | C2) - (C1 ^ C2).lshr(1)
+ KnownBits andResult = LHS & RHS;
+ KnownBits xorResult = LHS ^ RHS;
+ xorResult.Zero.lshrInPlace(1);
+ xorResult.One.lshrInPlace(1);
+ return computeForSatAddSub(/*Add*/ false, /*Signed*/ false, andResult,
+ xorResult);
+}
+
KnownBits KnownBits::mul(const KnownBits &LHS, const KnownBits &RHS,
bool NoUndefSelfMultiply) {
unsigned BitWidth = LHS.getBitWidth();
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