Expand this test to handle more cases (remainder and shifts) of zero.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@73839 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/VMCore/ConstantFold.cpp b/lib/VMCore/ConstantFold.cpp
index dc8fb39f1731c9fa2e996dd8b39a9a45686eac6d..3aab0cce37e4f4ecca388784c3a47ec58ed6759c 100644 (file)
--- a/lib/VMCore/ConstantFold.cpp
+++ b/lib/VMCore/ConstantFold.cpp
@@ -629,7 +629,7 @@ Constant *llvm::ConstantFoldBinaryInstruction(unsigned Opcode,
     }
   }
 
-  // Handle simplifications of the RHS when a constant int.
+  // Handle simplifications when the RHS is a constant int.
   if (const ConstantInt *CI2 = dyn_cast<ConstantInt>(C2)) {
     switch (Opcode) {
     case Instruction::Add:
@@ -773,13 +773,20 @@ Constant *llvm::ConstantFoldBinaryInstruction(unsigned Opcode,
       }
       }
     }
-    
-    // 0 / x -> 0.
-    if ((Opcode == Instruction::UDiv ||
-         Opcode == Instruction::SDiv) &&
-        CI1->isZero())
-      return const_cast<Constant*>(C1);
-    
+
+    switch (Opcode) {
+    case Instruction::SDiv:
+    case Instruction::UDiv:
+    case Instruction::URem:
+    case Instruction::SRem:
+    case Instruction::LShr:
+    case Instruction::AShr:
+    case Instruction::Shl:
+      if (CI1->equalsInt(0)) return const_cast<Constant*>(C1);
+      break;
+    default:
+      break;
+    }
   } else if (const ConstantFP *CFP1 = dyn_cast<ConstantFP>(C1)) {
     if (const ConstantFP *CFP2 = dyn_cast<ConstantFP>(C2)) {
       APFloat C1V = CFP1->getValueAPF();

diff --git a/test/Transforms/ConstProp/2009-06-20-constexpr-zero-lhs.ll b/test/Transforms/ConstProp/2009-06-20-constexpr-zero-lhs.ll
new file mode 100644 (file)
index 0000000..3322605
--- /dev/null
+++ b/test/Transforms/ConstProp/2009-06-20-constexpr-zero-lhs.ll
@@ -0,0 +1,11 @@
+; RUN: llvm-as < %s | llvm-dis | not grep ptrtoint
+; PR4424
+@G = external global i32
+@test1 = constant i32 sdiv (i32 0, i32 ptrtoint (i32* @G to i32))
+@test2 = constant i32 udiv (i32 0, i32 ptrtoint (i32* @G to i32))
+@test3 = constant i32 srem (i32 0, i32 ptrtoint (i32* @G to i32))
+@test4 = constant i32 urem (i32 0, i32 ptrtoint (i32* @G to i32))
+@test5 = constant i32 lshr (i32 0, i32 ptrtoint (i32* @G to i32))
+@test6 = constant i32 ashr (i32 0, i32 ptrtoint (i32* @G to i32))
+@test7 = constant i32 shl (i32 0, i32 ptrtoint (i32* @G to i32))
+