[SystemZ] Rework getInterleavedMemoryOpCost()

Model this function more closely after the BasicTTIImpl version, with
separate handling of loads and stores. For loads, the set of actually loaded
vectors is checked.

This makes it more readable and just slightly more accurate generally.

Review: Ulrich Weigand
https://reviews.llvm.org/D53071

llvm-svn: 345998

1 files changed, 149 insertions, 0 deletions

diff --git a/llvm/test/Transforms/LoopVectorize/SystemZ/mem-interleaving-costs-02.ll b/llvm/test/Transforms/LoopVectorize/SystemZ/mem-interleaving-costs-02.ll
new file mode 100644
index 00000000000..4c992cedd88
--- /dev/null
+++ b/llvm/test/Transforms/LoopVectorize/SystemZ/mem-interleaving-costs-02.ll
@@ -0,0 +1,149 @@
+; REQUIRES: asserts
+; RUN: opt -mtriple=s390x-unknown-linux -mcpu=z13 -loop-vectorize \
+; RUN:   -debug-only=loop-vectorize,vectorutils -max-interleave-group-factor=64\
+; RUN:   -disable-output < %s 2>&1 | FileCheck %s
+;
+; Check that some cost estimations for interleave groups make sense.
+
+; This loop is loading four i16 values at indices [0, 1, 2, 3], with a stride
+; of 4. At VF=4, memory interleaving means loading 4 * 4 * 16 bits = 2 vector
+; registers. Each of the 4 vector values must then be constructed from the
+; two vector registers using one vperm each, which gives a cost of 2 + 4 = 6.
+;
+; CHECK: LV: Checking a loop in "fun0"
+; CHECK: LV: Found an estimated cost of 6 for VF 4 For instruction:   %ld0 = load i16
+; CHECK: LV: Found an estimated cost of 0 for VF 4 For instruction:   %ld1 = load i16
+; CHECK: LV: Found an estimated cost of 0 for VF 4 For instruction:   %ld2 = load i16
+; CHECK: LV: Found an estimated cost of 0 for VF 4 For instruction:   %ld3 = load i16
+define void @fun0(i16 *%ptr, i16 *%dst) {
+entry:
+  br label %for.body
+
+for.body:
+  %ivptr = phi i16* [ %ptr.next, %for.body ], [ %ptr, %entry ]
+  %iv = phi i64 [ %inc, %for.body ], [ 0, %entry ]
+  %inc = add i64 %iv, 4
+  %ptr0 = getelementptr inbounds i16, i16* %ivptr, i64 0
+  %ld0 = load i16, i16* %ptr0
+  %ptr1 = getelementptr inbounds i16, i16* %ivptr, i64 1
+  %ld1 = load i16, i16* %ptr1
+  %ptr2 = getelementptr inbounds i16, i16* %ivptr, i64 2
+  %ld2 = load i16, i16* %ptr2
+  %ptr3 = getelementptr inbounds i16, i16* %ivptr, i64 3
+  %ld3 = load i16, i16* %ptr3
+  %a1 = add i16 %ld0, %ld1
+  %a2 = add i16 %a1, %ld2
+  %a3 = add i16 %a2, %ld3
+  %dstptr = getelementptr inbounds i16, i16* %dst, i64 %iv
+  store i16 %a3, i16* %dstptr
+  %ptr.next = getelementptr inbounds i16, i16* %ivptr, i64 4
+  %cmp = icmp eq i64 %inc, 100
+  br i1 %cmp, label %for.end, label %for.body
+
+for.end:
+  ret void
+}
+
+; This loop loads one i8 value in a stride of 3. At VF=16, this means loading
+; 3 vector registers, and then constructing the vector value with two vperms,
+; which gives a cost of 5.
+;
+; CHECK: LV: Checking a loop in "fun1"
+; CHECK: LV: Found an estimated cost of 5 for VF 16 For instruction:   %ld0 = load i8
+define void @fun1(i8 *%ptr, i8 *%dst) {
+entry:
+  br label %for.body
+
+for.body:
+  %ivptr = phi i8* [ %ptr.next, %for.body ], [ %ptr, %entry ]
+  %iv = phi i64 [ %inc, %for.body ], [ 0, %entry ]
+  %inc = add i64 %iv, 4
+  %ptr0 = getelementptr inbounds i8, i8* %ivptr, i64 0
+  %ld0 = load i8, i8* %ptr0
+  %dstptr = getelementptr inbounds i8, i8* %dst, i64 %iv
+  store i8 %ld0, i8* %dstptr
+  %ptr.next = getelementptr inbounds i8, i8* %ivptr, i64 3
+  %cmp = icmp eq i64 %inc, 100
+  br i1 %cmp, label %for.end, label %for.body
+
+for.end:
+  ret void
+}
+
+; This loop is loading 4 i8 values at indexes [0, 1, 2, 3], with a stride of
+; 32. At VF=2, this means loading 2 vector registers, and using 4 vperms to
+; produce the vector values, which gives a cost of 6.
+;
+; CHECK: LV: Checking a loop in "fun2"
+; CHECK: LV: Found an estimated cost of 6 for VF 2 For instruction:   %ld0 = load i8
+; CHECK: LV: Found an estimated cost of 0 for VF 2 For instruction:   %ld1 = load i8
+; CHECK: LV: Found an estimated cost of 0 for VF 2 For instruction:   %ld2 = load i8
+; CHECK: LV: Found an estimated cost of 0 for VF 2 For instruction:   %ld3 = load i8
+define void @fun2(i8 *%ptr, i8 *%dst) {
+entry:
+  br label %for.body
+
+for.body:
+  %ivptr = phi i8* [ %ptr.next, %for.body ], [ %ptr, %entry ]
+  %iv = phi i64 [ %inc, %for.body ], [ 0, %entry ]
+  %inc = add i64 %iv, 4
+  %ptr0 = getelementptr inbounds i8, i8* %ivptr, i64 0
+  %ld0 = load i8, i8* %ptr0
+  %ptr1 = getelementptr inbounds i8, i8* %ivptr, i64 1
+  %ld1 = load i8, i8* %ptr1
+  %ptr2 = getelementptr inbounds i8, i8* %ivptr, i64 2
+  %ld2 = load i8, i8* %ptr2
+  %ptr3 = getelementptr inbounds i8, i8* %ivptr, i64 3
+  %ld3 = load i8, i8* %ptr3
+  %a1 = add i8 %ld0, %ld1
+  %a2 = add i8 %a1, %ld2
+  %a3 = add i8 %a2, %ld3
+  %dstptr = getelementptr inbounds i8, i8* %dst, i64 %iv
+  store i8 %a3, i8* %dstptr
+  %ptr.next = getelementptr inbounds i8, i8* %ivptr, i64 32
+  %cmp = icmp eq i64 %inc, 100
+  br i1 %cmp, label %for.end, label %for.body
+
+for.end:
+  ret void
+}
+
+; This loop is loading 4 i8 values at indexes [0, 1, 2, 3], with a stride of
+; 30. At VF=2, this means loading 3 vector registers, and using 4 vperms to
+; produce the vector values, which gives a cost of 7. This is the same loop
+; as in fun2, except the stride makes the second iterations values overlap a
+; vector register boundary.
+;
+; CHECK: LV: Checking a loop in "fun3"
+; CHECK: LV: Found an estimated cost of 7 for VF 2 For instruction:   %ld0 = load i8
+; CHECK: LV: Found an estimated cost of 0 for VF 2 For instruction:   %ld1 = load i8
+; CHECK: LV: Found an estimated cost of 0 for VF 2 For instruction:   %ld2 = load i8
+; CHECK: LV: Found an estimated cost of 0 for VF 2 For instruction:   %ld3 = load i8
+define void @fun3(i8 *%ptr, i8 *%dst) {
+entry:
+  br label %for.body
+
+for.body:
+  %ivptr = phi i8* [ %ptr.next, %for.body ], [ %ptr, %entry ]
+  %iv = phi i64 [ %inc, %for.body ], [ 0, %entry ]
+  %inc = add i64 %iv, 4
+  %ptr0 = getelementptr inbounds i8, i8* %ivptr, i64 0
+  %ld0 = load i8, i8* %ptr0
+  %ptr1 = getelementptr inbounds i8, i8* %ivptr, i64 1
+  %ld1 = load i8, i8* %ptr1
+  %ptr2 = getelementptr inbounds i8, i8* %ivptr, i64 2
+  %ld2 = load i8, i8* %ptr2
+  %ptr3 = getelementptr inbounds i8, i8* %ivptr, i64 3
+  %ld3 = load i8, i8* %ptr3
+  %a1 = add i8 %ld0, %ld1
+  %a2 = add i8 %a1, %ld2
+  %a3 = add i8 %a2, %ld3
+  %dstptr = getelementptr inbounds i8, i8* %dst, i64 %iv
+  store i8 %a3, i8* %dstptr
+  %ptr.next = getelementptr inbounds i8, i8* %ivptr, i64 30
+  %cmp = icmp eq i64 %inc, 100
+  br i1 %cmp, label %for.end, label %for.body
+
+for.end:
+  ret void
+}