[PPC] Implement vmrgew and vmrgow instructions

[kbarton]

Summary

This patch adds support for the vector merge even word and vector merge odd word
instructions introduced in POWER8.

These are the Clang-related changes for http://reviews.llvm.org/D10704

All builtins are added in altivec.h and guarded with the POWER8_VECTOR macro.

[wschmidt]

LGTM.

[kbarton]

Committed revision 241293.

lib/Headers/altivec.h

 static vector float __ATTRS_o_ai vec_vmrglw(vector float __a,
                                             vector float __b) {
   return vec_perm(__a, __b,
                   (vector unsigned char)(0x08, 0x09, 0x0A, 0x0B, 0x18, 0x19,
                                          0x1A, 0x1B, 0x0C, 0x0D, 0x0E, 0x0F,
                                          0x1C, 0x1D, 0x1E, 0x1F));
 }
 
+
+#ifdef __POWER8_VECTOR__
+/* vec_mergee */
+
+static vector bool int __ATTRS_o_ai
+vec_mergee(vector bool int __a, vector bool int __b) {
+  return vec_perm(__a, __b, (vector unsigned char)
+                  (0x00, 0x01, 0x02, 0x03, 0x10, 0x11, 0x12, 0x13, 
+                   0x08, 0x09, 0x0A, 0x0B, 0x18, 0x19, 0x1A, 0x1B));
+}
+
+static vector signed int __ATTRS_o_ai
+vec_mergee(vector signed int __a, vector signed int __b) {
+  return vec_perm(__a, __b, (vector unsigned char)
+                  (0x00, 0x01, 0x02, 0x03, 0x10, 0x11, 0x12, 0x13, 
+                   0x08, 0x09, 0x0A, 0x0B, 0x18, 0x19, 0x1A, 0x1B));
+}
+
+static vector unsigned int __ATTRS_o_ai
+vec_mergee(vector unsigned int __a, vector unsigned int __b) {
+  return vec_perm(__a, __b, (vector unsigned char)
+                  (0x00, 0x01, 0x02, 0x03, 0x10, 0x11, 0x12, 0x13, 
+                   0x08, 0x09, 0x0A, 0x0B, 0x18, 0x19, 0x1A, 0x1B));
+}
+
+/* vec_mergeo */
+
+static vector bool int  __ATTRS_o_ai
+vec_mergeo(vector bool int __a, vector bool int __b) {
+  return vec_perm(__a, __b, (vector unsigned char)
+                  (0x04, 0x05, 0x06, 0x07, 0x14, 0x15, 0x16, 0x17,
+                   0x0C, 0x0D, 0x0E, 0x0F, 0x1C, 0x1D, 0x1E, 0x1F));
+}
+
+static vector signed int  __ATTRS_o_ai
+vec_mergeo(vector signed int __a, vector signed int __b) {
+  return vec_perm(__a, __b, (vector unsigned char)
+                  (0x04, 0x05, 0x06, 0x07, 0x14, 0x15, 0x16, 0x17,
+                   0x0C, 0x0D, 0x0E, 0x0F, 0x1C, 0x1D, 0x1E, 0x1F));
+}
+
+static vector unsigned int  __ATTRS_o_ai
+vec_mergeo(vector unsigned int __a, vector unsigned int __b) {
+  return vec_perm(__a, __b, (vector unsigned char)
+                  (0x04, 0x05, 0x06, 0x07, 0x14, 0x15, 0x16, 0x17,
+                   0x0C, 0x0D, 0x0E, 0x0F, 0x1C, 0x1D, 0x1E, 0x1F));
+}
+
+#endif
+
 /* vec_mfvscr */
 
 static vector unsigned short __attribute__((__always_inline__))
 vec_mfvscr(void) {
   return __builtin_altivec_mfvscr();
 }
 
 /* vec_min */

test/CodeGen/builtins-ppc-p8vector.c

 vector bool int res_vbi;
 vector bool long long res_vbll;
 vector signed long long res_vsll;
 vector unsigned long long res_vull;
 
 // CHECK-LABEL: define void @test1
 void test1() {
 
+  /* vec_mergee */  
+  res_vbi = vec_mergee(vbi, vbi);
+// CHECK: @llvm.ppc.altivec.vperm
+// CHECK-LE: @llvm.ppc.altivec.vperm
+  
+  res_vi = vec_mergee(vi, vi);
+// CHECK: @llvm.ppc.altivec.vperm
+// CHECK-LE: @llvm.ppc.altivec.vperm
+
+  res_vui = vec_mergee(vui, vui);
+// CHECK: @llvm.ppc.altivec.vperm
+// CHECK-LE: @llvm.ppc.altivec.vperm
+// CHECK-PPC: warning: implicit declaration of function 'vec_mergee'
+
+  /* vec_mergeo */
+  res_vbi = vec_mergeo(vbi, vbi);
+// CHECK: @llvm.ppc.altivec.vperm
+// CHECK-LE: @llvm.ppc.altivec.vperm
+
+  res_vi = vec_mergeo(vi, vi);
+// CHECK: @llvm.ppc.altivec.vperm
+// CHECK-LE: @llvm.ppc.altivec.vperm
+
+  res_vui = vec_mergeo(vui, vui);
+// CHECK: @llvm.ppc.altivec.vperm
+// CHECK-LE: @llvm.ppc.altivec.vperm
+// CHECK-PPC: warning: implicit declaration of function 'vec_mergeo'
+  
   /* vec_cmpeq */
   res_vbll = vec_cmpeq(vsll, vsll);
 // CHECK: @llvm.ppc.altivec.vcmpequd
 // CHECK-LE: @llvm.ppc.altivec.vcmpequd
 // CHECK-PPC: error: call to 'vec_cmpeq' is ambiguous
 
   res_vbll = vec_cmpeq(vull, vull);
 // CHECK: @llvm.ppc.altivec.vcmpequd