From 6d14dfe8f3766142e05da2e96e030b70f97e6a85 Mon Sep 17 00:00:00 2001
From: Haicheng Wu <haicheng@codeaurora.org>
Date: Fri, 22 Dec 2017 17:09:09 +0000
Subject: [InlineCost] Find more free binary operations

Currently, inline cost model considers a binary operator as free only if both
its operands are constants. Some simple cases are missing such as a + 0, a - a,
etc. This patch modifies visitBinaryOperator() to call SimplifyBinOp() without
going through simplifyInstruction() to get rid of the constant restriction.
Thus, visitAnd() and visitOr() are not needed.

Differential Revision: https://reviews.llvm.org/D41494

llvm-svn: 321366
---
 llvm/lib/Analysis/InlineCost.cpp | 58 +++++++++++++---------------------------
 1 file changed, 18 insertions(+), 40 deletions(-)

(limited to 'llvm/lib/Analysis')

diff --git a/llvm/lib/Analysis/InlineCost.cpp b/llvm/lib/Analysis/InlineCost.cpp
index 8d186e2d5af..b0cb29203a5 100644
--- a/llvm/lib/Analysis/InlineCost.cpp
+++ b/llvm/lib/Analysis/InlineCost.cpp
@@ -249,8 +249,6 @@ class CallAnalyzer : public InstVisitor<CallAnalyzer, bool> {
   bool visitCastInst(CastInst &I);
   bool visitUnaryInstruction(UnaryInstruction &I);
   bool visitCmpInst(CmpInst &I);
-  bool visitAnd(BinaryOperator &I);
-  bool visitOr(BinaryOperator &I);
   bool visitSub(BinaryOperator &I);
   bool visitBinaryOperator(BinaryOperator &I);
   bool visitLoad(LoadInst &I);
@@ -1021,34 +1019,6 @@ bool CallAnalyzer::visitCmpInst(CmpInst &I) {
   return false;
 }
 
-bool CallAnalyzer::visitOr(BinaryOperator &I) {
-  // This is necessary because the generic simplify instruction only works if
-  // both operands are constants.
-  for (unsigned i = 0; i < 2; ++i) {
-    if (ConstantInt *C = dyn_cast_or_null<ConstantInt>(
-            SimplifiedValues.lookup(I.getOperand(i))))
-      if (C->isAllOnesValue()) {
-        SimplifiedValues[&I] = C;
-        return true;
-      }
-  }
-  return Base::visitOr(I);
-}
-
-bool CallAnalyzer::visitAnd(BinaryOperator &I) {
-  // This is necessary because the generic simplify instruction only works if
-  // both operands are constants.
-  for (unsigned i = 0; i < 2; ++i) {
-    if (ConstantInt *C = dyn_cast_or_null<ConstantInt>(
-            SimplifiedValues.lookup(I.getOperand(i))))
-      if (C->isZero()) {
-        SimplifiedValues[&I] = C;
-        return true;
-      }
-  }
-  return Base::visitAnd(I);
-}
-
 bool CallAnalyzer::visitSub(BinaryOperator &I) {
   // Try to handle a special case: we can fold computing the difference of two
   // constant-related pointers.
@@ -1078,17 +1048,25 @@ bool CallAnalyzer::visitSub(BinaryOperator &I) {
 
 bool CallAnalyzer::visitBinaryOperator(BinaryOperator &I) {
   Value *LHS = I.getOperand(0), *RHS = I.getOperand(1);
-  auto Evaluate = [&](SmallVectorImpl<Constant *> &COps) {
-    Value *SimpleV = nullptr;
-    if (auto FI = dyn_cast<FPMathOperator>(&I))
-      SimpleV = SimplifyFPBinOp(I.getOpcode(), COps[0], COps[1],
-                                FI->getFastMathFlags(), DL);
-    else
-      SimpleV = SimplifyBinOp(I.getOpcode(), COps[0], COps[1], DL);
-    return dyn_cast_or_null<Constant>(SimpleV);
-  };
+  Constant *CLHS = dyn_cast<Constant>(LHS);
+  if (!CLHS)
+    CLHS = SimplifiedValues.lookup(LHS);
+  Constant *CRHS = dyn_cast<Constant>(RHS);
+  if (!CRHS)
+    CRHS = SimplifiedValues.lookup(RHS);
+
+  Value *SimpleV = nullptr;
+  if (auto FI = dyn_cast<FPMathOperator>(&I))
+    SimpleV = SimplifyFPBinOp(I.getOpcode(), CLHS ? CLHS : LHS,
+                              CRHS ? CRHS : RHS, FI->getFastMathFlags(), DL);
+  else
+    SimpleV =
+        SimplifyBinOp(I.getOpcode(), CLHS ? CLHS : LHS, CRHS ? CRHS : RHS, DL);
+
+  if (Constant *C = dyn_cast_or_null<Constant>(SimpleV))
+    SimplifiedValues[&I] = C;
 
-  if (simplifyInstruction(I, Evaluate))
+  if (SimpleV)
     return true;
 
   // Disable any SROA on arguments to arbitrary, unsimplified binary operators.
-- 
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