Implement bit-accurate sext instruction.
This patch fixes test/Integer/2007-01-17-TruncSext.ll
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@33394 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/ExecutionEngine/Interpreter/Execution.cpp b/lib/ExecutionEngine/Interpreter/Execution.cpp
index 61624f3..91c7c57 100644
--- a/lib/ExecutionEngine/Interpreter/Execution.cpp
+++ b/lib/ExecutionEngine/Interpreter/Execution.cpp
@@ -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;
}