[llvm-commits] CVS: llvm/lib/ExecutionEngine/Interpreter/Execution.cpp

[Reid Spencer]

Changes in directory llvm/lib/ExecutionEngine/Interpreter:

Execution.cpp updated: 1.162 -> 1.163
---
Log message:

Implement bit-accurate sext instruction. 
This patch fixes test/Integer/2007-01-17-TruncSext.ll


---
Diffs of the changes:  (+14 -10)

 Execution.cpp |   24 ++++++++++++++----------
 1 files changed, 14 insertions(+), 10 deletions(-)


Index: llvm/lib/ExecutionEngine/Interpreter/Execution.cpp
diff -u llvm/lib/ExecutionEngine/Interpreter/Execution.cpp:1.162 llvm/lib/ExecutionEngine/Interpreter/Execution.cpp:1.163
--- llvm/lib/ExecutionEngine/Interpreter/Execution.cpp:1.162	Wed Jan 17 20:12:51 2007
+++ llvm/lib/ExecutionEngine/Interpreter/Execution.cpp	Sat Jan 20 02:32:52 2007
@@ -1347,21 +1347,25 @@
   assert(SBitWidth <= 64 && DBitWidth <= 64  && 
          "Integer types > 64 bits not supported");
   assert(SBitWidth < DBitWidth && "Invalid sign extend");
-  int64_t Extended = 0;
-  if (SBitWidth == 1)
-    // For sign extension from bool, we must extend the source bits.
-    Extended = 0 - (Src.Int1Val & 1);
-  else if (SBitWidth <= 8)
-    Extended = (int64_t) (int8_t)Src.Int8Val;
+
+  // Normalize to a 64-bit value.
+  uint64_t Normalized = 0;
+  if (SBitWidth <= 8)
+    Normalized = Src.Int8Val;
   else if (SBitWidth <= 16)
-    Extended = (int64_t) (int16_t)Src.Int16Val;
+    Normalized = Src.Int16Val;
   else if (SBitWidth <= 32)
-    Extended = (int64_t) (int32_t)Src.Int32Val;
+    Normalized = Src.Int32Val;
   else 
-    Extended = (int64_t) Src.Int64Val;
+    Normalized = Src.Int64Val;
+
+  // Now do the bit-accurate sign extension manually.
+  bool isSigned = (Normalized & (1 << (SBitWidth-1))) != 0;
+  if (isSigned)
+    Normalized |= ~SITy->getBitMask();
 
   // Now that we have a sign extended value, assign it to the destination
-  INTEGER_ASSIGN(Dest, DBitWidth, Extended);
+  INTEGER_ASSIGN(Dest, DBitWidth, Normalized);
   return Dest;
 }