ARM cost model: Increase the cost for vector casts that use the stack
Increase the cost of v8/v16-i8 to v8/v16-i32 casts and truncates as the backend
currently lowers those using stack accesses.
This was responsible for a significant degradation on
MultiSource/Benchmarks/Trimaran/enc-pc1/enc-pc1
where we vectorize one loop to a vector factor of 16. After this patch we select
a vector factor of 4 which will generate reasonable code.
unsigned char cle[32];
void test(short c) {
unsigned short compte;
for (compte = 0; compte <= 31; compte++) {
cle[compte] = cle[compte] ^ c;
}
}
radar://13220512
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@176898 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Target/ARM/ARMTargetTransformInfo.cpp b/lib/Target/ARM/ARMTargetTransformInfo.cpp
index 01c04b4..eef282e 100644
--- a/lib/Target/ARM/ARMTargetTransformInfo.cpp
+++ b/lib/Target/ARM/ARMTargetTransformInfo.cpp
@@ -194,6 +194,14 @@
{ ISD::TRUNCATE, MVT::v4i32, MVT::v4i64, 0 },
{ ISD::TRUNCATE, MVT::v4i16, MVT::v4i32, 1 },
+ // Operations that we legalize using load/stores to the stack.
+ { ISD::SIGN_EXTEND, MVT::v16i32, MVT::v16i8, 16*2 + 4*4 },
+ { ISD::ZERO_EXTEND, MVT::v16i32, MVT::v16i8, 16*2 + 4*3 },
+ { ISD::SIGN_EXTEND, MVT::v8i32, MVT::v8i8, 8*2 + 2*4 },
+ { ISD::ZERO_EXTEND, MVT::v8i32, MVT::v8i8, 8*2 + 2*3 },
+ { ISD::TRUNCATE, MVT::v16i8, MVT::v16i32, 4*1 + 16*2 + 2*1 },
+ { ISD::TRUNCATE, MVT::v8i8, MVT::v8i32, 2*1 + 8*2 + 1 },
+
// Vector float <-> i32 conversions.
{ ISD::SINT_TO_FP, MVT::v4f32, MVT::v4i32, 1 },
{ ISD::UINT_TO_FP, MVT::v4f32, MVT::v4i32, 1 },
diff --git a/test/Analysis/CostModel/ARM/cast.ll b/test/Analysis/CostModel/ARM/cast.ll
index 464b6ec..779c438 100644
--- a/test/Analysis/CostModel/ARM/cast.ll
+++ b/test/Analysis/CostModel/ARM/cast.ll
@@ -152,6 +152,20 @@
; CHECK: cost of 10 {{.*}} uitofp
%r69 = uitofp i64 undef to double
+ ; Vector cast cost of instructions lowering the cast to the stack.
+ ; CHECK: cost of 24 {{.*}} sext
+ %r70 = sext <8 x i8> undef to <8 x i32>
+ ; CHECK: cost of 48 {{.*}} sext
+ %r71 = sext <16 x i8> undef to <16 x i32>
+ ; CHECK: cost of 22 {{.*}} zext
+ %r72 = zext <8 x i8> undef to <8 x i32>
+ ; CHECK: cost of 44 {{.*}} zext
+ %r73 = zext <16 x i8> undef to <16 x i32>
+ ; CHECK: cost of 19 {{.*}} trunc
+ %r74 = trunc <8 x i32> undef to <8 x i8>
+ ; CHECK: cost of 38 {{.*}} trunc
+ %r75 = trunc <16 x i32> undef to <16 x i8>
+
;CHECK: cost of 0 {{.*}} ret
ret i32 undef
}
