From 75775939fa6ded14975d4571d1933b57dc2ce383 Mon Sep 17 00:00:00 2001
From: Tom Stellard <thomas.stellard@amd.com>
Date: Tue, 26 May 2015 15:55:50 +0000
Subject: [PATCH] AsmMatcherEmitter: Add an option to override custom
 converters for InstAlias

If there is an InstAlias defined for an instruction that had a custom
converter (AsmMatchConverter), then when the alias is matched,
the custom converter will be used rather than the converter generated
by the InstAlias.

This patch adds the UseInstAsmMatchConverter field to the InstAlias
class, which allows you to override this behavior and force the
converter generated by the InstAlias to be used.

This is required for some future improvemnts to the R600 assembler.

Differential Revision: http://reviews.llvm.org/D9083

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@238210 91177308-0d34-0410-b5e6-96231b3b80d8
---
 include/llvm/Target/Target.td        |  9 +++++++++
 utils/TableGen/AsmMatcherEmitter.cpp | 15 ++++++++++++---
 2 files changed, 21 insertions(+), 3 deletions(-)

diff --git a/include/llvm/Target/Target.td b/include/llvm/Target/Target.td
index 1ff8db8c2e6..ec8a12df9fc 100644
--- a/include/llvm/Target/Target.td
+++ b/include/llvm/Target/Target.td
@@ -1006,6 +1006,15 @@ class InstAlias<string Asm, dag Result, int Emit = 1> {
 
   // Predicates - Predicates that must be true for this to match.
   list<Predicate> Predicates = [];
+
+	// If the instruction specified in Result has defined an AsmMatchConverter
+  // then setting this to 1 will cause the alias to use the AsmMatchConverter
+  // function when converting the OperandVector into an MCInst instead of the
+  // function that is generated by the dag Result.
+  // Setting this to 0 will cause the alias to ignore the Result instruction's
+  // defined AsmMatchConverter and instead use the function generated by the
+  // dag Result.
+  bit UseInstAsmMatchConverter = 1;
 }
 
 //===----------------------------------------------------------------------===//
diff --git a/utils/TableGen/AsmMatcherEmitter.cpp b/utils/TableGen/AsmMatcherEmitter.cpp
index 9dfdc117b7b..d8f26193954 100644
--- a/utils/TableGen/AsmMatcherEmitter.cpp
+++ b/utils/TableGen/AsmMatcherEmitter.cpp
@@ -438,12 +438,21 @@ struct MatchableInfo {
   /// If this instruction is deprecated in some form.
   bool HasDeprecation;
 
+  /// If this is an alias, this is use to determine whether or not to using
+  /// the conversion function defined by the instruction's AsmMatchConverter
+  /// or to use the function generated by the alias.
+  bool UseInstAsmMatchConverter;
+
   MatchableInfo(const CodeGenInstruction &CGI)
-    : AsmVariantID(0), AsmString(CGI.AsmString), TheDef(CGI.TheDef), DefRec(&CGI) {
+    : AsmVariantID(0), AsmString(CGI.AsmString), TheDef(CGI.TheDef), DefRec(&CGI),
+      UseInstAsmMatchConverter(true) {
   }
 
   MatchableInfo(std::unique_ptr<const CodeGenInstAlias> Alias)
-    : AsmVariantID(0), AsmString(Alias->AsmString), TheDef(Alias->TheDef), DefRec(Alias.release()) {
+    : AsmVariantID(0), AsmString(Alias->AsmString), TheDef(Alias->TheDef),
+      DefRec(Alias.release()),
+      UseInstAsmMatchConverter(
+        TheDef->getValueAsBit("UseInstAsmMatchConverter")) {
   }
 
   ~MatchableInfo() {
@@ -1749,7 +1758,7 @@ static void emitConvertFuncs(CodeGenTarget &Target, StringRef ClassName,
     // Check if we have a custom match function.
     std::string AsmMatchConverter =
       II->getResultInst()->TheDef->getValueAsString("AsmMatchConverter");
-    if (!AsmMatchConverter.empty()) {
+    if (!AsmMatchConverter.empty() && II->UseInstAsmMatchConverter) {
       std::string Signature = "ConvertCustom_" + AsmMatchConverter;
       II->ConversionFnKind = Signature;
 
-- 
2.34.1