From ad74e435bad01cc633d5b05375959c54067c3dd7 Mon Sep 17 00:00:00 2001
From: rain2133 <1370973498@qq.com>
Date: Mon, 18 Aug 2025 21:55:57 +0800
Subject: [PATCH] =?UTF-8?q?[midend-GSR]=E4=BF=AE=E5=A4=8D=E9=94=99?=
 =?UTF-8?q?=E8=AF=AF=E7=9A=84=E4=BB=A3=E6=95=B0=E7=AE=80=E5=8C=96?=
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---
 .../Pass/Optimize/GlobalStrengthReduction.cpp | 57 +++++++++++++------
 1 file changed, 41 insertions(+), 16 deletions(-)

diff --git a/src/midend/Pass/Optimize/GlobalStrengthReduction.cpp b/src/midend/Pass/Optimize/GlobalStrengthReduction.cpp
index e15a9c5..e8254a2 100644
--- a/src/midend/Pass/Optimize/GlobalStrengthReduction.cpp
+++ b/src/midend/Pass/Optimize/GlobalStrengthReduction.cpp
@@ -390,8 +390,8 @@ bool GlobalStrengthReductionContext::optimizeLogical(BinaryInst *inst) {
       return true;
     }
     
-    // x && 1 = x
-    if (isConstantInt(rhs, constVal) && constVal == 1) {
+    // x && -1 = x
+    if (isConstantInt(rhs, constVal) && constVal == -1) {
       if (DEBUG) {
         std::cout << "        Algebraic: " << inst->getName() << " = x && 1 -> x" << std::endl;
       }
@@ -416,15 +416,6 @@ bool GlobalStrengthReductionContext::optimizeLogical(BinaryInst *inst) {
       replaceWithOptimized(inst, lhs);
       return true;
     }
-    
-    // x || 1 = 1
-    if (isConstantInt(rhs, constVal) && constVal == 1) {
-      if (DEBUG) {
-        std::cout << "        Algebraic: " << inst->getName() << " = x || 1 -> 1" << std::endl;
-      }
-      replaceWithOptimized(inst, getConstantInt(1));
-      return true;
-    }
 
     // x || x = x
     if (lhs == rhs) {
@@ -630,16 +621,50 @@ bool GlobalStrengthReductionContext::reduceDivision(BinaryInst *inst) {
 
   // x / 2^n = x >> n (对于无符号除法或已知为正数的情况)
   if (isConstantInt(rhs, constVal) && constVal > 0 && isPowerOfTwo(constVal)) {
+    builder->setPosition(inst->getParent(), inst->getParent()->findInstIterator(inst));
     int shiftAmount = log2OfPowerOfTwo(constVal);
+    // 有符号除法校正：(x + (x >> 31) & mask) >> k
+    int maskValue = constVal - 1;
+    
+    // x >> 31 (算术右移获取符号位)
+    Value* signShift = ConstantInteger::get(31);
+    Value* signBits = builder->createBinaryInst(
+      Instruction::Kind::kSra,  // 算术右移
+      lhs->getType(),
+      lhs,
+      signShift
+    );
+    
+    // (x >> 31) & mask
+    Value* mask = ConstantInteger::get(maskValue);
+    Value* correction = builder->createBinaryInst(
+      Instruction::Kind::kAnd,
+      lhs->getType(),
+      signBits,
+      mask
+    );
+    
+    // x + correction
+    Value* corrected = builder->createAddInst(lhs, correction);
+    
+    // (x + correction) >> k
+    Value* divShift = ConstantInteger::get(shiftAmount);
+    Value* shiftInst = builder->createBinaryInst(
+      Instruction::Kind::kSra,  // 算术右移
+      lhs->getType(),
+      corrected,
+      divShift
+    );
+
     if (DEBUG) {
       std::cout << "        StrengthReduction: " << inst->getName() 
-                << " = x / " << constVal << " -> x >> " << shiftAmount << std::endl;
+                << " = x / " << constVal << " -> (x + (x >> 31) & mask) >> " << shiftAmount << std::endl;
     }
     
-    builder->setPosition(inst->getParent(), inst->getParent()->findInstIterator(inst));
-    Value* divisor_minus_1 = ConstantInteger::get(constVal - 1);
-    Value* adjusted = builder->createAddInst(lhs, divisor_minus_1);
-    Value* shiftInst = builder->createBinaryInst(Instruction::kSra, Type::getIntType(), adjusted, getConstantInt(shiftAmount));
+    // builder->setPosition(inst->getParent(), inst->getParent()->findInstIterator(inst));
+    // Value* divisor_minus_1 = ConstantInteger::get(constVal - 1);
+    // Value* adjusted = builder->createAddInst(lhs, divisor_minus_1);
+    // Value* shiftInst = builder->createBinaryInst(Instruction::kSra, Type::getIntType(), adjusted, getConstantInt(shiftAmount));
     replaceWithOptimized(inst, shiftInst);
     strengthReductionCount++;
     return true;