[DOXYGEN] Improved doxygen comments for x86 intrinsics headers.

Tagged instruction names with <c> INSTR_NAME </c> to display them in typewriter font.

In the past, \c command was used, unfortunately it applied to only one word. 
<c> .. </c> has the same meaning, but applies to all words in between the tags.

llvm-svn: 289249
diff --git a/clang/lib/Headers/pmmintrin.h b/clang/lib/Headers/pmmintrin.h
index 5b10580..5f201fb 100644
--- a/clang/lib/Headers/pmmintrin.h
+++ b/clang/lib/Headers/pmmintrin.h
@@ -37,7 +37,7 @@
 ///
 /// \headerfile <x86intrin.h>
 ///
-/// This intrinsic corresponds to the \c VLDDQU instruction.
+/// This intrinsic corresponds to the <c> VLDDQU </c> instruction.
 ///
 /// \param __p
 ///    A pointer to a 128-bit integer vector containing integer values.
@@ -53,7 +53,7 @@
 ///
 /// \headerfile <x86intrin.h>
 ///
-/// This intrinsic corresponds to the \c VADDSUBPS instruction.
+/// This intrinsic corresponds to the <c> VADDSUBPS </c> instruction.
 ///
 /// \param __a
 ///    A 128-bit vector of [4 x float] containing the left source operand.
@@ -72,7 +72,7 @@
 ///
 /// \headerfile <x86intrin.h>
 ///
-/// This intrinsic corresponds to the \c VHADDPS instruction.
+/// This intrinsic corresponds to the <c> VHADDPS </c> instruction.
 ///
 /// \param __a
 ///    A 128-bit vector of [4 x float] containing one of the source operands.
@@ -95,7 +95,7 @@
 ///
 /// \headerfile <x86intrin.h>
 ///
-/// This intrinsic corresponds to the \c VHSUBPS instruction.
+/// This intrinsic corresponds to the <c> VHSUBPS </c> instruction.
 ///
 /// \param __a
 ///    A 128-bit vector of [4 x float] containing one of the source operands.
@@ -123,7 +123,7 @@
 ///
 /// \headerfile <x86intrin.h>
 ///
-/// This intrinsic corresponds to the \c VMOVSHDUP instruction.
+/// This intrinsic corresponds to the <c> VMOVSHDUP </c> instruction.
 ///
 /// \param __a
 ///    A 128-bit vector of [4 x float].
@@ -145,7 +145,7 @@
 ///
 /// \headerfile <x86intrin.h>
 ///
-/// This intrinsic corresponds to the \c VMOVSLDUP instruction.
+/// This intrinsic corresponds to the <c> VMOVSLDUP </c> instruction.
 ///
 /// \param __a
 ///    A 128-bit vector of [4 x float].
@@ -162,7 +162,7 @@
 ///
 /// \headerfile <x86intrin.h>
 ///
-/// This intrinsic corresponds to the \c VADDSUBPD instruction.
+/// This intrinsic corresponds to the <c> VADDSUBPD </c> instruction.
 ///
 /// \param __a
 ///    A 128-bit vector of [2 x double] containing the left source operand.
@@ -181,7 +181,7 @@
 ///
 /// \headerfile <x86intrin.h>
 ///
-/// This intrinsic corresponds to the \c VHADDPD instruction.
+/// This intrinsic corresponds to the <c> VHADDPD </c> instruction.
 ///
 /// \param __a
 ///    A 128-bit vector of [2 x double] containing one of the source operands.
@@ -204,7 +204,7 @@
 ///
 /// \headerfile <x86intrin.h>
 ///
-/// This intrinsic corresponds to the \c VHSUBPD instruction.
+/// This intrinsic corresponds to the <c> VHSUBPD </c> instruction.
 ///
 /// \param __a
 ///    A 128-bit vector of [2 x double] containing one of the source operands.
@@ -231,7 +231,7 @@
 /// __m128d _mm_loaddup_pd(double const * dp);
 /// \endcode
 ///
-/// This intrinsic corresponds to the \c VMOVDDUP instruction.
+/// This intrinsic corresponds to the <c> VMOVDDUP </c> instruction.
 ///
 /// \param dp
 ///    A pointer to a double-precision value to be moved and duplicated.
@@ -245,7 +245,7 @@
 ///
 /// \headerfile <x86intrin.h>
 ///
-/// This intrinsic corresponds to the \c VMOVDDUP instruction.
+/// This intrinsic corresponds to the <c> VMOVDDUP </c> instruction.
 ///
 /// \param __a
 ///    A 128-bit vector of [2 x double]. Bits [63:0] are written to bits
@@ -272,7 +272,7 @@
 ///
 /// \headerfile <x86intrin.h>
 ///
-/// This intrinsic corresponds to the \c MONITOR instruction.
+/// This intrinsic corresponds to the <c> MONITOR </c> instruction.
 ///
 /// \param __p
 ///    The memory range to be monitored. The size of the range is determined by
@@ -293,7 +293,7 @@
 ///
 /// \headerfile <x86intrin.h>
 ///
-/// This intrinsic corresponds to the \c MWAIT instruction.
+/// This intrinsic corresponds to the <c> MWAIT </c> instruction.
 ///
 /// \param __extensions
 ///    Optional extensions for the monitoring state, which may vary by