Make sure that we don't call getZExtValue on values > 64 bits.

Thanks Benjamin for noticing this.

llvm-svn: 162749

2 files changed, 15 insertions, 8 deletions

diff --git a/llvm/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp b/llvm/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp
index e104a0a9798..5eba463ec05 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineMulDivRem.cpp
@@ -462,11 +462,11 @@ Instruction *InstCombiner::visitUDiv(BinaryOperator &I) {
     }
   }
 
-  // Udiv ((Lshl x, c1) , c2) ->  x / (C1 * 1<<C2);
-  if (Constant *C = dyn_cast<Constant>(Op1)) {
+  // Udiv ((Lshl x, C1) , C2) ->  x / (C2 * 1<<C1);
+  if (ConstantInt *C2 = dyn_cast<ConstantInt>(Op1)) {
     Value *X = 0, *C1 = 0;
-    if (match(Op0, m_LShr(m_Value(X), m_Value(C1)))) {
-      uint64_t NC = cast<ConstantInt>(C)->getZExtValue() *
+    if (match(Op0, m_LShr(m_Value(X), m_Value(C1))) && C2->getBitWidth() < 65) {
+      uint64_t NC = cast<ConstantInt>(C2)->getZExtValue() *
                     (1<< cast<ConstantInt>(C1)->getZExtValue());
       return BinaryOperator::CreateUDiv(X, ConstantInt::get(I.getType(), NC));
     }
@@ -543,11 +543,11 @@ Instruction *InstCombiner::visitSDiv(BinaryOperator &I) {
                                           ConstantExpr::getNeg(RHS));
   }
 
-  // Sdiv ((Ashl x, c1) , c2) ->  x / (C1 * 1<<C2);
-  if (Constant *C = dyn_cast<Constant>(Op1)) {
+  // Sdiv ((Ashl x, C1) , C2) ->  x / (C2 * 1<<C1);
+  if (ConstantInt *C2 = dyn_cast<ConstantInt>(Op1)) {
     Value *X = 0, *C1 = 0;
-    if (match(Op0, m_AShr(m_Value(X), m_Value(C1)))) {
-      uint64_t NC = cast<ConstantInt>(C)->getZExtValue() *
+    if (match(Op0, m_AShr(m_Value(X), m_Value(C1))) && C2->getBitWidth() < 65) {
+      uint64_t NC = cast<ConstantInt>(C2)->getZExtValue() *
                     (1<< cast<ConstantInt>(C1)->getZExtValue());
       return BinaryOperator::CreateSDiv(X, ConstantInt::get(I.getType(), NC));
     }
diff --git a/llvm/test/Transforms/InstCombine/2012-08-28-udiv_ashl.ll b/llvm/test/Transforms/InstCombine/2012-08-28-udiv_ashl.ll
index 9f52119248e..1bede348931 100644
--- a/llvm/test/Transforms/InstCombine/2012-08-28-udiv_ashl.ll
+++ b/llvm/test/Transforms/InstCombine/2012-08-28-udiv_ashl.ll
@@ -48,3 +48,10 @@ entry:
   %div1 = sdiv i32 %div, 100
   ret i32 %div1
 }
+
+define i80 @no_crash_i80(i80 %x) {
+entry:
+  %div = lshr i80 %x, 2
+  %div1 = udiv i80 %div, 100
+  ret i80 %div1
+}