Preserve analysis info.

[oota-llvm.git] / lib / Target / SubtargetFeature.cpp

diff --git a/lib/Target/SubtargetFeature.cpp b/lib/Target/SubtargetFeature.cpp
index 80621232c9e98b049ed491d85f3bb5d730927944..d783f8b778982dbd9dc7dcf47052738100b35142 100644 (file)
--- a/lib/Target/SubtargetFeature.cpp
+++ b/lib/Target/SubtargetFeature.cpp
@@ -15,6 +15,7 @@
 #include "llvm/ADT/StringExtras.h"
 #include "llvm/Support/Streams.h"
 #include <algorithm>
+#include <ostream>
 #include <cassert>
 #include <cctype>
 using namespace llvm;
@@ -198,6 +199,43 @@ void SubtargetFeatures::setCPUIfNone(const std::string &String) {
   if (Features[0].empty()) setCPU(String);
 }
 
+/// SetImpliedBits - For each feature that is (transitively) implied by this
+/// feature, set it.
+/// 
+static
+void SetImpliedBits(uint32_t &Bits, const SubtargetFeatureKV *FeatureEntry,
+                    const SubtargetFeatureKV *FeatureTable,
+                    size_t FeatureTableSize) {
+  for (size_t i = 0; i < FeatureTableSize; ++i) {
+    const SubtargetFeatureKV &FE = FeatureTable[i];
+
+    if (FeatureEntry->Value == FE.Value) continue;
+
+    if (FeatureEntry->Implies & FE.Value) {
+      Bits |= FE.Value;
+      SetImpliedBits(Bits, &FE, FeatureTable, FeatureTableSize);
+    }
+  }
+}
+
+/// ClearImpliedBits - For each feature that (transitively) implies this
+/// feature, clear it.
+/// 
+static
+void ClearImpliedBits(uint32_t &Bits, const SubtargetFeatureKV *FeatureEntry,
+                      const SubtargetFeatureKV *FeatureTable,
+                      size_t FeatureTableSize) {
+  for (size_t i = 0; i < FeatureTableSize; ++i) {
+    const SubtargetFeatureKV &FE = FeatureTable[i];
+
+    if (FeatureEntry->Value == FE.Value) continue;
+
+    if (FE.Implies & FeatureEntry->Value) {
+      Bits &= ~FE.Value;
+      ClearImpliedBits(Bits, &FE, FeatureTable, FeatureTableSize);
+    }
+  }
+}
 
 /// getBits - Get feature bits.
 ///
@@ -230,6 +268,13 @@ uint32_t SubtargetFeatures::getBits(const SubtargetFeatureKV *CPUTable,
   if (CPUEntry) {
     // Set base feature bits
     Bits = CPUEntry->Value;
+
+    // Set the feature implied by this CPU feature, if any.
+    for (size_t i = 0; i < FeatureTableSize; ++i) {
+      const SubtargetFeatureKV &FE = FeatureTable[i];
+      if (CPUEntry->Value & FE.Value)
+        SetImpliedBits(Bits, &FE, FeatureTable, FeatureTableSize);
+    }
   } else {
     cerr << "'" << Features[0]
          << "' is not a recognized processor for this target"
@@ -250,8 +295,17 @@ uint32_t SubtargetFeatures::getBits(const SubtargetFeatureKV *CPUTable,
     // If there is a match
     if (FeatureEntry) {
       // Enable/disable feature in bits
-      if (isEnabled(Feature)) Bits |=  FeatureEntry->Value;
-      else                    Bits &= ~FeatureEntry->Value;
+      if (isEnabled(Feature)) {
+        Bits |=  FeatureEntry->Value;
+
+        // For each feature that this implies, set it.
+        SetImpliedBits(Bits, FeatureEntry, FeatureTable, FeatureTableSize);
+      } else {
+        Bits &= ~FeatureEntry->Value;
+
+        // For each feature that implies this, clear it.
+        ClearImpliedBits(Bits, FeatureEntry, FeatureTable, FeatureTableSize);
+      }
     } else {
       cerr << "'" << Feature
            << "' is not a recognized feature for this target"
@@ -259,6 +313,7 @@ uint32_t SubtargetFeatures::getBits(const SubtargetFeatureKV *CPUTable,
            << "\n";
     }
   }
+
   return Bits;
 }