Add a PPC inline asm constraint type for single CR bits

This adds support for the PPC "wc" inline asm constraint (used for allocating
individual CR bits). Support for this constraint type was recently added to the
LLVM PowerPC backend. Although gcc does not currently support allocating
individual CR bits, this identifier choice has been coordinated with the gcc
PowerPC team, and will be marked as reserved for this purpose in the gcc
constraints.md file.

Prior to this change, none of the multi-character PPC constraints were handled
correctly (the '^' escape character was not being added as required by the
parsing code in LLVM). This should now be fixed. I'll add tests for these other
constraints as support is added for them in the backend.

llvm-svn: 202658

1 files changed, 15 insertions, 0 deletions

diff --git a/clang/lib/Basic/Targets.cpp b/clang/lib/Basic/Targets.cpp
index 4a87717693a..1a59ec62086 100644
--- a/clang/lib/Basic/Targets.cpp
+++ b/clang/lib/Basic/Targets.cpp
@@ -788,6 +788,7 @@ public:
         case 'f':// VSX vector register to hold vector float data
         case 's':// VSX vector register to hold scalar float data
         case 'a':// Any VSX register
+        case 'c':// An individual CR bit
           break;
         default:
           return false;
@@ -863,6 +864,20 @@ public:
     }
     return true;
   }
+  virtual std::string convertConstraint(const char *&Constraint) const {
+    std::string R;
+    switch (*Constraint) {
+    case 'e':
+    case 'w':
+      // Two-character constraint; add "^" hint for later parsing.
+      R = std::string("^") + std::string(Constraint, 2);
+      Constraint++;
+      break;
+    default:
+      return TargetInfo::convertConstraint(Constraint);
+    }
+    return R;
+  }
   virtual const char *getClobbers() const {
     return "";
   }