[TableGen] Suppress type validation when parsing pattern fragments

Currently, any attempt to define a PatFrag involving any floating-point
only (or vector only) node causes a hard assertion failure in TableGen
if the current target does not have any floating-point (or vector)
types.

This is annoying if you want to provide convenience fragments in common
code (e.g. include/llvm/Target/TargetSelectionDAG.td) that is parsed on
all platforms, including those that miss such types.

But really, there's no reason not accept this when parsing the fragment
-- of course it would be an error for such a target to actually *use*
such a fragment anywhere, but as long as it doesn't, I think TableGen
shouldn't error out.

The immediate cause of the assertion failure is the test inside the
ValidateOnExit destructor. This patch simply disables that check while
infering types during parsing of pattern fragments (only).

Reviewed By: hfinkel, kparzysz

Differential Revision: https://reviews.llvm.org/D48887



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@337023 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 22 insertions, 4 deletions

diff --git a/utils/TableGen/CodeGenDAGPatterns.cpp b/utils/TableGen/CodeGenDAGPatterns.cpp
index e40d5bb56a5..c0ddfeb4f43 100644
--- a/utils/TableGen/CodeGenDAGPatterns.cpp
+++ b/utils/TableGen/CodeGenDAGPatterns.cpp
@@ -808,7 +808,7 @@ TypeSetByHwMode TypeInfer::getLegalTypes() {
 
 #ifndef NDEBUG
 TypeInfer::ValidateOnExit::~ValidateOnExit() {
-  if (!VTS.validate()) {
+  if (Infer.Validate && !VTS.validate()) {
     dbgs() << "Type set is empty for each HW mode:\n"
               "possible type contradiction in the pattern below "
               "(use -print-records with llvm-tblgen to see all "
@@ -3056,9 +3056,15 @@ void CodeGenDAGPatterns::ParsePatternFragments(bool OutFrags) {
     ThePat.InlinePatternFragments();
 
     // Infer as many types as possible.  Don't worry about it if we don't infer
-    // all of them, some may depend on the inputs of the pattern.
-    ThePat.InferAllTypes();
-    ThePat.resetError();
+    // all of them, some may depend on the inputs of the pattern.  Also, don't
+    // validate type sets; validation may cause spurious failures e.g. if a
+    // fragment needs floating-point types but the current target does not have
+    // any (this is only an error if that fragment is ever used!).
+    {
+      TypeInfer::SuppressValidation SV(ThePat.getInfer());
+      ThePat.InferAllTypes();
+      ThePat.resetError();
+    }
 
     // If debugging, print out the pattern fragment result.
     LLVM_DEBUG(ThePat.dump());
diff --git a/utils/TableGen/CodeGenDAGPatterns.h b/utils/TableGen/CodeGenDAGPatterns.h
index e4523797edf..c682f3d3268 100644
--- a/utils/TableGen/CodeGenDAGPatterns.h
+++ b/utils/TableGen/CodeGenDAGPatterns.h
@@ -333,9 +333,21 @@ struct TypeInfer {
     TypeSetByHwMode &VTS;
   };
 
+  struct SuppressValidation {
+    SuppressValidation(TypeInfer &TI) : Infer(TI), SavedValidate(TI.Validate) {
+      Infer.Validate = false;
+    }
+    ~SuppressValidation() {
+      Infer.Validate = SavedValidate;
+    }
+    TypeInfer &Infer;
+    bool SavedValidate;
+  };
+
   TreePattern &TP;
   unsigned ForceMode;     // Mode to use when set.
   bool CodeGen = false;   // Set during generation of matcher code.
+  bool Validate = true;   // Indicate whether to validate types.
 
 private:
   TypeSetByHwMode getLegalTypes();