[llvm-commits] [llvm] r73839 - in /llvm/trunk: lib/VMCore/ConstantFold.cpp test/Transforms/ConstProp/2009-06-20-constexpr-zero-lhs.ll

[Nick Lewycky]

Author: nicholas
Date: Sat Jun 20 20:56:41 2009
New Revision: 73839

URL: http://llvm.org/viewvc/llvm-project?rev=73839&view=rev
Log:
Expand this test to handle more cases (remainder and shifts) of zero.

Added:
    llvm/trunk/test/Transforms/ConstProp/2009-06-20-constexpr-zero-lhs.ll
      - copied, changed from r73835, llvm/trunk/test/Transforms/ConstProp/div-zero.ll
Modified:
    llvm/trunk/lib/VMCore/ConstantFold.cpp

Modified: llvm/trunk/lib/VMCore/ConstantFold.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/VMCore/ConstantFold.cpp?rev=73839&r1=73838&r2=73839&view=diff

==============================================================================
--- llvm/trunk/lib/VMCore/ConstantFold.cpp (original)
+++ llvm/trunk/lib/VMCore/ConstantFold.cpp Sat Jun 20 20:56:41 2009
@@ -629,7 +629,7 @@
     }
   }
 
-  // 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 @@
       }
       }
     }
-    
-    // 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();

Copied: llvm/trunk/test/Transforms/ConstProp/2009-06-20-constexpr-zero-lhs.ll (from r73835, llvm/trunk/test/Transforms/ConstProp/div-zero.ll)
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/ConstProp/2009-06-20-constexpr-zero-lhs.ll?p2=llvm/trunk/test/Transforms/ConstProp/2009-06-20-constexpr-zero-lhs.ll&p1=llvm/trunk/test/Transforms/ConstProp/div-zero.ll&r1=73835&r2=73839&rev=73839&view=diff

==============================================================================
--- llvm/trunk/test/Transforms/ConstProp/div-zero.ll (original)
+++ llvm/trunk/test/Transforms/ConstProp/2009-06-20-constexpr-zero-lhs.ll Sat Jun 20 20:56:41 2009
@@ -1,12 +1,11 @@
-; RUN: llvm-as < %s | opt -instcombine | llvm-dis | grep {ret i32 0}
+; RUN: llvm-as < %s | llvm-dis | not grep ptrtoint
 ; PR4424
-declare void @ext()
-
-define i32 @foo(i32 %ptr) {
-entry:
-        %zero = sub i32 %ptr, %ptr              ; <i32> [#uses=1]
-        %div_zero = sdiv i32 %zero, ptrtoint (i32* getelementptr (i32* null,
-i32 1) to i32)             ; <i32> [#uses=1]
-        ret i32 %div_zero
-}
+ at G = external global i32
+ at test1 = constant i32 sdiv (i32 0, i32 ptrtoint (i32* @G to i32))
+ at test2 = constant i32 udiv (i32 0, i32 ptrtoint (i32* @G to i32))
+ at test3 = constant i32 srem (i32 0, i32 ptrtoint (i32* @G to i32))
+ at test4 = constant i32 urem (i32 0, i32 ptrtoint (i32* @G to i32))
+ at test5 = constant i32 lshr (i32 0, i32 ptrtoint (i32* @G to i32))
+ at test6 = constant i32 ashr (i32 0, i32 ptrtoint (i32* @G to i32))
+ at test7 = constant i32 shl (i32 0, i32 ptrtoint (i32* @G to i32))