Reland [llvm-ml] Fix RIP-relative addressing for ptr operands (#108061)

Relands #107618 with fix for assertion triggered by OpenMP runtime MASM
assembly source.

Author: nga888

llvm/lib/Target/X86/AsmParser/X86AsmParser.cpp

@@ -2707,7 +2707,8 @@ bool X86AsmParser::parseIntelOperand(OperandVector &Operands, StringRef Name) {
   bool MaybeDirectBranchDest = true;
 
   if (Parser.isParsingMasm()) {
-    if (is64BitMode() && SM.getElementSize() > 0) {
+    if (is64BitMode() &&
+        ((PtrInOperand && !IndexReg) || SM.getElementSize() > 0)) {
       DefaultBaseReg = X86::RIP;
     }
     if (IsUnconditionalBranch) {

llvm/test/tools/llvm-ml/rip_relative_addressing.asm

@@ -53,4 +53,14 @@ mov eax, [t8]
 ; CHECK-LABEL: t8:
 ; CHECK: mov eax, dword ptr [t8]
 
-END
+t9:
+mov eax, dword ptr [bar]
+; CHECK-LABEL: t9:
+; CHECK-32: mov eax, dword ptr [bar]
+; CHECK-64: mov eax, dword ptr [rip + bar]
+
+t10:
+mov ebx, dword ptr [4*eax]
+; CHECK: mov ebx, dword ptr [4*eax]
+
+END