Fix llvm-mc handing of x86 instructions that take 8-bit unsigned immediates.

llvm-mc gives an "invalid operand" error for instructions that take an unsigned
immediate which have the high bit set such as:
    pblendw $0xc5, %xmm2, %xmm1
llvm-mc treats all x86 immediates as signed values and range checks them.
A small number of x86 instructions use the imm8 field as a set of bits.
This change only changes those instructions and where the high bit is not
ignored.  The others remain unchanged.

llvm-svn: 136287

1 files changed, 15 insertions, 0 deletions

diff --git a/llvm/lib/Target/X86/AsmParser/X86AsmParser.cpp b/llvm/lib/Target/X86/AsmParser/X86AsmParser.cpp
index e4adff6f9fb..efa8a6e1547 100644
--- a/llvm/lib/Target/X86/AsmParser/X86AsmParser.cpp
+++ b/llvm/lib/Target/X86/AsmParser/X86AsmParser.cpp
@@ -226,6 +226,21 @@ struct X86Operand : public MCParsedAsmOperand {
             (0x00000000FFFFFF80ULL <= Value && Value <= 0x00000000FFFFFFFFULL)||
             (0xFFFFFFFFFFFFFF80ULL <= Value && Value <= 0xFFFFFFFFFFFFFFFFULL));
   }
+  bool isImmZExtu32u8() const {
+    if (!isImm())
+      return false;
+
+    // If this isn't a constant expr, just assume it fits and let relaxation
+    // handle it.
+    const MCConstantExpr *CE = dyn_cast<MCConstantExpr>(getImm());
+    if (!CE)
+      return true;
+
+    // Otherwise, check the value is in a range that makes sense for this
+    // extension.
+    uint64_t Value = CE->getValue();
+    return (Value <= 0x00000000000000FFULL);
+  }
   bool isImmSExti64i8() const {
     if (!isImm())
       return false;