Fix integer undefined behavior due to signed left shift overflow in LLVM.

Reviewed offline by chandlerc.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@162623 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 8 insertions, 11 deletions

diff --git a/lib/Target/CellSPU/SPUAsmPrinter.cpp b/lib/Target/CellSPU/SPUAsmPrinter.cpp
index 03d5a9a..3396e8b 100644
--- a/lib/Target/CellSPU/SPUAsmPrinter.cpp
+++ b/lib/Target/CellSPU/SPUAsmPrinter.cpp
@@ -130,8 +130,7 @@ namespace {
     void
     printS10ImmOperand(const MachineInstr *MI, unsigned OpNo, raw_ostream &O)
     {
-      short value = (short) (((int) MI->getOperand(OpNo).getImm() << 16)
-                             >> 16);
+      short value = MI->getOperand(OpNo).getImm();
       assert((value >= -(1 << 9) && value <= (1 << 9) - 1)
              && "Invalid s10 argument");
       O << value;
@@ -140,8 +139,7 @@ namespace {
     void
     printU10ImmOperand(const MachineInstr *MI, unsigned OpNo, raw_ostream &O)
     {
-      short value = (short) (((int) MI->getOperand(OpNo).getImm() << 16)
-                             >> 16);
+      short value = MI->getOperand(OpNo).getImm();
       assert((value <= (1 << 10) - 1) && "Invalid u10 argument");
       O << value;
     }
diff --git a/lib/Target/CellSPU/SPUISelDAGToDAG.cpp b/lib/Target/CellSPU/SPUISelDAGToDAG.cpp
index c27caea..425371d 100644
--- a/lib/Target/CellSPU/SPUISelDAGToDAG.cpp
+++ b/lib/Target/CellSPU/SPUISelDAGToDAG.cpp
@@ -83,12 +83,10 @@ namespace {
       return true;
     } else if (vt == MVT::i32) {
       int32_t i_val = (int32_t) CN->getZExtValue();
-      short s_val = (short) i_val;
-      return i_val == s_val;
+      return i_val == SignExtend32<16>(i_val);
     } else {
       int64_t i_val = (int64_t) CN->getZExtValue();
-      short s_val = (short) i_val;
-      return i_val == s_val;
+      return i_val == SignExtend64<16>(i_val);
     }
   }
 
@@ -99,9 +97,10 @@ namespace {
     EVT vt = FPN->getValueType(0);
     if (vt == MVT::f32) {
       int val = FloatToBits(FPN->getValueAPF().convertToFloat());
-      int sval = (int) ((val << 16) >> 16);
-      Imm = (short) val;
-      return val == sval;
+      if (val == SignExtend32<16>(val)) {
+        Imm = (short) val;
+        return true;
+      }
     }
 
     return false;