r292659 - [Altivec] Change vec_sl to a << (b % (sizeof(a) * 8))
Tim Shen via cfe-commits
cfe-commits at lists.llvm.org
Fri Jan 20 14:05:34 PST 2017
Author: timshen
Date: Fri Jan 20 16:05:33 2017
New Revision: 292659
URL: http://llvm.org/viewvc/llvm-project?rev=292659&view=rev
Log:
[Altivec] Change vec_sl to a << (b % (sizeof(a) * 8))
For a << b (as original vec_sl does), if b >= sizeof(a) * 8, the
behavior is undefined. However, Power instructions do define the
behavior, which is equivalent to a << (b % (sizeof(a) * 8)).
This patch changes altivec.h to use a << (b % (sizeof(a) * 8)), to
ensure the consistent semantic of the instructions. Then it combines
the generated multiple instructions back to a single shift.
This patch handles left shift only. Right shift, on the other hand, is
more complicated, considering arithematic/logical right shift.
Differential Revision: https://reviews.llvm.org/D28037
Modified:
cfe/trunk/lib/Headers/altivec.h
cfe/trunk/test/CodeGen/builtins-ppc-altivec.c
Modified: cfe/trunk/lib/Headers/altivec.h
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Headers/altivec.h?rev=292659&r1=292658&r2=292659&view=diff
==============================================================================
--- cfe/trunk/lib/Headers/altivec.h (original)
+++ cfe/trunk/lib/Headers/altivec.h Fri Jan 20 16:05:33 2017
@@ -8045,45 +8045,51 @@ static __inline__ vector float __ATTRS_o
/* vec_sl */
-static __inline__ vector signed char __ATTRS_o_ai
-vec_sl(vector signed char __a, vector unsigned char __b) {
- return __a << (vector signed char)__b;
-}
-
+// vec_sl does modulo arithmetic on __b first, so __b is allowed to be more
+// than the length of __a.
static __inline__ vector unsigned char __ATTRS_o_ai
vec_sl(vector unsigned char __a, vector unsigned char __b) {
- return __a << __b;
+ return __a << (__b %
+ (vector unsigned char)(sizeof(unsigned char) * __CHAR_BIT__));
}
-static __inline__ vector short __ATTRS_o_ai vec_sl(vector short __a,
- vector unsigned short __b) {
- return __a << (vector short)__b;
+static __inline__ vector signed char __ATTRS_o_ai
+vec_sl(vector signed char __a, vector unsigned char __b) {
+ return (vector signed char)vec_sl((vector unsigned char)__a, __b);
}
static __inline__ vector unsigned short __ATTRS_o_ai
vec_sl(vector unsigned short __a, vector unsigned short __b) {
- return __a << __b;
+ return __a << (__b % (vector unsigned short)(sizeof(unsigned short) *
+ __CHAR_BIT__));
}
-static __inline__ vector int __ATTRS_o_ai vec_sl(vector int __a,
- vector unsigned int __b) {
- return __a << (vector int)__b;
+static __inline__ vector short __ATTRS_o_ai vec_sl(vector short __a,
+ vector unsigned short __b) {
+ return (vector short)vec_sl((vector unsigned short)__a, __b);
}
static __inline__ vector unsigned int __ATTRS_o_ai
vec_sl(vector unsigned int __a, vector unsigned int __b) {
- return __a << __b;
+ return __a << (__b %
+ (vector unsigned int)(sizeof(unsigned int) * __CHAR_BIT__));
}
-#ifdef __POWER8_VECTOR__
-static __inline__ vector signed long long __ATTRS_o_ai
-vec_sl(vector signed long long __a, vector unsigned long long __b) {
- return __a << (vector long long)__b;
+static __inline__ vector int __ATTRS_o_ai vec_sl(vector int __a,
+ vector unsigned int __b) {
+ return (vector int)vec_sl((vector unsigned int)__a, __b);
}
+#ifdef __POWER8_VECTOR__
static __inline__ vector unsigned long long __ATTRS_o_ai
vec_sl(vector unsigned long long __a, vector unsigned long long __b) {
- return __a << __b;
+ return __a << (__b % (vector unsigned long long)(sizeof(unsigned long long) *
+ __CHAR_BIT__));
+}
+
+static __inline__ vector long long __ATTRS_o_ai
+vec_sl(vector long long __a, vector unsigned long long __b) {
+ return (vector long long)vec_sl((vector unsigned long long)__a, __b);
}
#endif
Modified: cfe/trunk/test/CodeGen/builtins-ppc-altivec.c
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/CodeGen/builtins-ppc-altivec.c?rev=292659&r1=292658&r2=292659&view=diff
==============================================================================
--- cfe/trunk/test/CodeGen/builtins-ppc-altivec.c (original)
+++ cfe/trunk/test/CodeGen/builtins-ppc-altivec.c Fri Jan 20 16:05:33 2017
@@ -3419,28 +3419,40 @@ void test6() {
/* vec_sl */
res_vsc = vec_sl(vsc, vuc);
-// CHECK: shl <16 x i8>
-// CHECK-LE: shl <16 x i8>
+// CHECK: [[UREM:[0-9a-zA-Z%.]+]] = urem <16 x i8> {{[0-9a-zA-Z%.]+}}, <i8 8, i8 8, i8 8, i8 8, i8 8, i8 8, i8 8, i8 8, i8 8, i8 8, i8 8, i8 8, i8 8, i8 8, i8 8, i8 8>
+// CHECK: shl <16 x i8> {{[0-9a-zA-Z%.]+}}, [[UREM]]
+// CHECK-LE: [[UREM:[0-9a-zA-Z%.]+]] = urem <16 x i8> {{[0-9a-zA-Z%.]+}}, <i8 8, i8 8, i8 8, i8 8, i8 8, i8 8, i8 8, i8 8, i8 8, i8 8, i8 8, i8 8, i8 8, i8 8, i8 8, i8 8>
+// CHECK-LE: shl <16 x i8> {{[0-9a-zA-Z%.]+}}, [[UREM]]
res_vuc = vec_sl(vuc, vuc);
-// CHECK: shl <16 x i8>
-// CHECK-LE: shl <16 x i8>
+// CHECK: [[UREM:[0-9a-zA-Z%.]+]] = urem <16 x i8> {{[0-9a-zA-Z%.]+}}, <i8 8, i8 8, i8 8, i8 8, i8 8, i8 8, i8 8, i8 8, i8 8, i8 8, i8 8, i8 8, i8 8, i8 8, i8 8, i8 8>
+// CHECK: shl <16 x i8> {{[0-9a-zA-Z%.]+}}, [[UREM]]
+// CHECK-LE: [[UREM:[0-9a-zA-Z%.]+]] = urem <16 x i8> {{[0-9a-zA-Z%.]+}}, <i8 8, i8 8, i8 8, i8 8, i8 8, i8 8, i8 8, i8 8, i8 8, i8 8, i8 8, i8 8, i8 8, i8 8, i8 8, i8 8>
+// CHECK-LE: shl <16 x i8> {{[0-9a-zA-Z%.]+}}, [[UREM]]
res_vs = vec_sl(vs, vus);
-// CHECK: shl <8 x i16>
-// CHECK-LE: shl <8 x i16>
+// CHECK: [[UREM:[0-9a-zA-Z%.]+]] = urem <8 x i16> {{[0-9a-zA-Z%.]+}}, <i16 16, i16 16, i16 16, i16 16, i16 16, i16 16, i16 16, i16 16>
+// CHECK: shl <8 x i16> {{[0-9a-zA-Z%.]+}}, [[UREM]]
+// CHECK-LE: [[UREM:[0-9a-zA-Z%.]+]] = urem <8 x i16> {{[0-9a-zA-Z%.]+}}, <i16 16, i16 16, i16 16, i16 16, i16 16, i16 16, i16 16, i16 16>
+// CHECK-LE: shl <8 x i16> {{[0-9a-zA-Z%.]+}}, [[UREM]]
res_vus = vec_sl(vus, vus);
-// CHECK: shl <8 x i16>
-// CHECK-LE: shl <8 x i16>
+// CHECK: [[UREM:[0-9a-zA-Z%.]+]] = urem <8 x i16> {{[0-9a-zA-Z%.]+}}, <i16 16, i16 16, i16 16, i16 16, i16 16, i16 16, i16 16, i16 16>
+// CHECK: shl <8 x i16> {{[0-9a-zA-Z%.]+}}, [[UREM]]
+// CHECK-LE: [[UREM:[0-9a-zA-Z%.]+]] = urem <8 x i16> {{[0-9a-zA-Z%.]+}}, <i16 16, i16 16, i16 16, i16 16, i16 16, i16 16, i16 16, i16 16>
+// CHECK-LE: shl <8 x i16> {{[0-9a-zA-Z%.]+}}, [[UREM]]
res_vi = vec_sl(vi, vui);
-// CHECK: shl <4 x i32>
-// CHECK-LE: shl <4 x i32>
+// CHECK: [[UREM:[0-9a-zA-Z%.]+]] = urem <4 x i32> {{[0-9a-zA-Z%.]+}}, <i32 32, i32 32, i32 32, i32 32>
+// CHECK: shl <4 x i32> {{[0-9a-zA-Z%.]+}}, [[UREM]]
+// CHECK-LE: [[UREM:[0-9a-zA-Z%.]+]] = urem <4 x i32> {{[0-9a-zA-Z%.]+}}, <i32 32, i32 32, i32 32, i32 32>
+// CHECK-LE: shl <4 x i32> {{[0-9a-zA-Z%.]+}}, [[UREM]]
res_vui = vec_sl(vui, vui);
-// CHECK: shl <4 x i32>
-// CHECK-LE: shl <4 x i32>
+// CHECK: [[UREM:[0-9a-zA-Z%.]+]] = urem <4 x i32> {{[0-9a-zA-Z%.]+}}, <i32 32, i32 32, i32 32, i32 32>
+// CHECK: shl <4 x i32> {{[0-9a-zA-Z%.]+}}, [[UREM]]
+// CHECK-LE: [[UREM:[0-9a-zA-Z%.]+]] = urem <4 x i32> {{[0-9a-zA-Z%.]+}}, <i32 32, i32 32, i32 32, i32 32>
+// CHECK-LE: shl <4 x i32> {{[0-9a-zA-Z%.]+}}, [[UREM]]
res_vsc = vec_vslb(vsc, vuc);
// CHECK: shl <16 x i8>
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