[asm] Make EmitMSInlineAsmStr and EmitGCCInlineAsmStr more alike

https://reviews.llvm.org/D71677 copied a bunch of code from
EmitGCCInlineAsmStr() to EmitMSInlineAsmStr() but made a few small
(likely unintentional) changes. This makes these pieces look the same.

No behavior change.

(Why are these functions two copies? No great reason as far as I can tell.
https://reviews.llvm.org/rG1778831a3d1d24ab6545635f63da4d9c5f8f0ac7 did the
split; we might want to undo them at some point. But PR23933 suggests
that a bigger change is planned for this file in the future, so keeping
this incremental for now.)

Differential Revision: https://reviews.llvm.org/D113924

llvm/lib/CodeGen/AsmPrinter/AsmPrinterInlineAsm.cpp

@@ -176,7 +176,7 @@ static void EmitMSInlineAsmStr(const char *AsmStr, const MachineInstr *MI,
       // If we have ${:foo}, then this is not a real operand reference, it is a
       // "magic" string reference, just like in .td files.  Arrange to call
       // PrintSpecial.
-      if (HasCurlyBraces && LastEmitted[0] == ':') {
+      if (HasCurlyBraces && *LastEmitted == ':') {
         ++LastEmitted;
         const char *StrStart = LastEmitted;
         const char *StrEnd = strchr(StrStart, '}');
@@ -200,7 +200,7 @@ static void EmitMSInlineAsmStr(const char *AsmStr, const MachineInstr *MI,
                            Twine(AsmStr) + "'");
       LastEmitted = IDEnd;
 
-      if (Val >= NumOperands-1)
+      if (Val >= NumOperands - 1)
         report_fatal_error("Invalid $ operand number in inline asm string: '" +
                            Twine(AsmStr) + "'");
 
@@ -367,6 +367,10 @@ static void EmitGCCInlineAsmStr(const char *AsmStr, const MachineInstr *MI,
                            Twine(AsmStr) + "'");
       LastEmitted = IDEnd;
 
+      if (Val >= NumOperands - 1)
+        report_fatal_error("Invalid $ operand number in inline asm string: '" +
+                           Twine(AsmStr) + "'");
+
       char Modifier[2] = { 0, 0 };
 
       if (HasCurlyBraces) {
@@ -388,10 +392,6 @@ static void EmitGCCInlineAsmStr(const char *AsmStr, const MachineInstr *MI,
         ++LastEmitted;    // Consume '}' character.
       }
 
-      if (Val >= NumOperands-1)
-        report_fatal_error("Invalid $ operand number in inline asm string: '" +
-                           Twine(AsmStr) + "'");
-
       // Okay, we finally have a value number.  Ask the target to print this
       // operand!
       if (CurVariant == -1 || CurVariant == AsmPrinterVariant) {