Pull in r215811 from upstream llvm trunk (by Nico Weber):

  arm asm: Let .fpu enable instructions, PR20447.

  I'm not very happy with duplicating the fpu->feature mapping in ARMAsmParser.cpp
  and in clang's driver. See the bug for a patch that doesn't do that, and the
  review thread [1] for why this duplication exists.

  1: http://lists.cs.uiuc.edu/pipermail/llvm-commits/Week-of-Mon-20140811/231052.html

This makes the .fpu directive work properly, so we can successfully
assemble several .S files using the directive, under lib/libc/arm.

Introduced here: http://svnweb.freebsd.org/changeset/base/275280

Index: lib/Target/ARM/AsmParser/ARMAsmParser.cpp
===================================================================
--- lib/Target/ARM/AsmParser/ARMAsmParser.cpp
+++ lib/Target/ARM/AsmParser/ARMAsmParser.cpp
@@ -8621,6 +8621,30 @@ bool ARMAsmParser::parseDirectiveCPU(SMLoc L) {
   return false;
 }
 
+// FIXME: This is duplicated in getARMFPUFeatures() in
+// tools/clang/lib/Driver/Tools.cpp
+static const struct {
+  const unsigned Fpu;
+  const uint64_t Enabled;
+  const uint64_t Disabled;
+} Fpus[] = {
+      {ARM::VFP, ARM::FeatureVFP2, ARM::FeatureNEON},
+      {ARM::VFPV2, ARM::FeatureVFP2, ARM::FeatureNEON},
+      {ARM::VFPV3, ARM::FeatureVFP3, ARM::FeatureNEON},
+      {ARM::VFPV3_D16, ARM::FeatureVFP3 | ARM::FeatureD16, ARM::FeatureNEON},
+      {ARM::VFPV4, ARM::FeatureVFP4, ARM::FeatureNEON},
+      {ARM::VFPV4_D16, ARM::FeatureVFP4 | ARM::FeatureD16, ARM::FeatureNEON},
+      {ARM::FP_ARMV8, ARM::FeatureFPARMv8,
+       ARM::FeatureNEON | ARM::FeatureCrypto},
+      {ARM::NEON, ARM::FeatureNEON, 0},
+      {ARM::NEON_VFPV4, ARM::FeatureVFP4 | ARM::FeatureNEON, 0},
+      {ARM::NEON_FP_ARMV8, ARM::FeatureFPARMv8 | ARM::FeatureNEON,
+       ARM::FeatureCrypto},
+      {ARM::CRYPTO_NEON_FP_ARMV8,
+       ARM::FeatureFPARMv8 | ARM::FeatureNEON | ARM::FeatureCrypto, 0},
+      {ARM::SOFTVFP, 0, 0},
+};
+
 /// parseDirectiveFPU
 ///  ::= .fpu str
 bool ARMAsmParser::parseDirectiveFPU(SMLoc L) {
@@ -8636,6 +8660,18 @@ bool ARMAsmParser::parseDirectiveFPU(SMLoc L) {
     return false;
   }
 
+  for (const auto &Fpu : Fpus) {
+    if (Fpu.Fpu != ID)
+      continue;
+
+    // Need to toggle features that should be on but are off and that
+    // should off but are on.
+    unsigned Toggle = (Fpu.Enabled & ~STI.getFeatureBits()) |
+                      (Fpu.Disabled & STI.getFeatureBits());
+    setAvailableFeatures(ComputeAvailableFeatures(STI.ToggleFeature(Toggle)));
+    break;
+  }
+
   getTargetStreamer().emitFPU(ID);
   return false;
 }
Index: test/MC/ARM/directive-fpu-instrs.s
===================================================================
--- test/MC/ARM/directive-fpu-instrs.s
+++ test/MC/ARM/directive-fpu-instrs.s
@@ -0,0 +1,16 @@
+// RUN: llvm-mc -triple armv7-unknown-linux-gnueabi -mattr=+vfp3,+d16,-neon %s
+
+.fpu neon
+VAND d3, d5, d5
+vldr d21, [r7, #296]
+
+@ .thumb should not disable the prior .fpu neon
+.thumb
+
+vmov q4, q11 @ v4si
+str r6, [r7, #264]
+mov r6, r5
+vldr d21, [r7, #296]
+add r9, r7, #216
+
+fstmfdd sp!, {d8, d9, d10, d11, d12, d13, d14, d15}