[clang] 38a34e2 - [PowerPC] Use modulo arithmetic for vec_extract in altivec.h

[Nemanja Ivanovic via cfe-commits]

Author: Nemanja Ivanovic
Date: 2021-03-01T19:49:26-06:00
New Revision: 38a34e207f30747a4b0288d97ce67e422bf5f363

URL: https://github.com/llvm/llvm-project/commit/38a34e207f30747a4b0288d97ce67e422bf5f363
DIFF: https://github.com/llvm/llvm-project/commit/38a34e207f30747a4b0288d97ce67e422bf5f363.diff

LOG: [PowerPC] Use modulo arithmetic for vec_extract in altivec.h

These interfaces are not covered in the ELFv2 ABI but are rather
implemented to emulate those available in GCC/XLC. However, the
ones in the other compilers are documented to perform modulo
arithmetic on the element number. This patch just brings clang
inline with the other compilers at -O0 (with optimization, clang
already does the right thing).

Added: 
    

Modified: 
    clang/lib/Headers/altivec.h

Removed: 
    


################################################################################
diff  --git a/clang/lib/Headers/altivec.h b/clang/lib/Headers/altivec.h
index 4d50d47d51b5..402f3b389496 100644
--- a/clang/lib/Headers/altivec.h
+++ b/clang/lib/Headers/altivec.h
@@ -12915,73 +12915,75 @@ vec_vxor(vector bool long long __a, vector bool long long __b) {
 /* vec_extract */
 
 static __inline__ signed char __ATTRS_o_ai vec_extract(vector signed char __a,
-                                                       int __b) {
-  return __a[__b];
+                                                       unsigned int __b) {
+  return __a[__b & 0xf];
 }
 
 static __inline__ unsigned char __ATTRS_o_ai
-vec_extract(vector unsigned char __a, int __b) {
-  return __a[__b];
+vec_extract(vector unsigned char __a, unsigned int __b) {
+  return __a[__b & 0xf];
 }
 
 static __inline__ unsigned char __ATTRS_o_ai vec_extract(vector bool char __a,
-                                                         int __b) {
-  return __a[__b];
+                                                         unsigned int __b) {
+  return __a[__b & 0xf];
 }
 
 static __inline__ signed short __ATTRS_o_ai vec_extract(vector signed short __a,
-                                                        int __b) {
-  return __a[__b];
+                                                        unsigned int __b) {
+  return __a[__b & 0x7];
 }
 
 static __inline__ unsigned short __ATTRS_o_ai
-vec_extract(vector unsigned short __a, int __b) {
-  return __a[__b];
+vec_extract(vector unsigned short __a, unsigned int __b) {
+  return __a[__b & 0x7];
 }
 
 static __inline__ unsigned short __ATTRS_o_ai vec_extract(vector bool short __a,
-                                                          int __b) {
-  return __a[__b];
+                                                          unsigned int __b) {
+  return __a[__b & 0x7];
 }
 
 static __inline__ signed int __ATTRS_o_ai vec_extract(vector signed int __a,
-                                                      int __b) {
-  return __a[__b];
+                                                      unsigned int __b) {
+  return __a[__b & 0x3];
 }
 
 static __inline__ unsigned int __ATTRS_o_ai vec_extract(vector unsigned int __a,
-                                                        int __b) {
-  return __a[__b];
+                                                        unsigned int __b) {
+  return __a[__b & 0x3];
 }
 
 static __inline__ unsigned int __ATTRS_o_ai vec_extract(vector bool int __a,
-                                                        int __b) {
-  return __a[__b];
+                                                        unsigned int __b) {
+  return __a[__b & 0x3];
 }
 
 #ifdef __VSX__
 static __inline__ signed long long __ATTRS_o_ai
-vec_extract(vector signed long long __a, int __b) {
-  return __a[__b];
+vec_extract(vector signed long long __a, unsigned int __b) {
+  return __a[__b & 0x1];
 }
 
 static __inline__ unsigned long long __ATTRS_o_ai
-vec_extract(vector unsigned long long __a, int __b) {
-  return __a[__b];
+vec_extract(vector unsigned long long __a, unsigned int __b) {
+  return __a[__b & 0x1];
 }
 
 static __inline__ unsigned long long __ATTRS_o_ai
-vec_extract(vector bool long long __a, int __b) {
-  return __a[__b];
+vec_extract(vector bool long long __a, unsigned int __b) {
+  return __a[__b & 0x1];
 }
 
-static __inline__ double __ATTRS_o_ai vec_extract(vector double __a, int __b) {
-  return __a[__b];
+static __inline__ double __ATTRS_o_ai vec_extract(vector double __a,
+                                                  unsigned int __b) {
+  return __a[__b & 0x1];
 }
 #endif
 
-static __inline__ float __ATTRS_o_ai vec_extract(vector float __a, int __b) {
-  return __a[__b];
+static __inline__ float __ATTRS_o_ai vec_extract(vector float __a,
+                                                 unsigned int __b) {
+  return __a[__b & 0x3];
 }
 
 #ifdef __POWER9_VECTOR__