[SystemZ] Don't assert for i128 vectors in getInterleavedMemoryOpCost()

[JonPsson1]

This assert does not seem justified given that the LoopVectorizer can form interleave groups containing i128 elements where the number of elements per vector is indeed just one.

(csmith)

[llvmbot]

@llvm/pr-subscribers-llvm-transforms

Author: Jonas Paulsson (JonPsson1)

Changes

This assert does not seem justified given that the LoopVectorizer can form interleave groups containing i128 elements where the number of elements per vector is indeed just one.

(csmith)

---

Full diff: https://github.com/llvm/llvm-project/pull/78009.diff

2 Files Affected:

• (modified) llvm/lib/Target/SystemZ/SystemZTargetTransformInfo.cpp (-1)
• (added) llvm/test/Transforms/LoopVectorize/SystemZ/mem-interleaving-costs-03.ll (+42)

diff --git a/llvm/lib/Target/SystemZ/SystemZTargetTransformInfo.cpp b/llvm/lib/Target/SystemZ/SystemZTargetTransformInfo.cpp
index 1f97e0f761c04d..e21d3090ba2fd1 100644
--- a/llvm/lib/Target/SystemZ/SystemZTargetTransformInfo.cpp
+++ b/llvm/lib/Target/SystemZ/SystemZTargetTransformInfo.cpp
@@ -1236,7 +1236,6 @@ InstructionCost SystemZTTIImpl::getInterleavedMemoryOpCost(
     // dst vector for vperm (S.A.).
     unsigned NumSrcVecs = std::min(NumEltsPerVecReg, Factor);
     unsigned NumDstVecs = NumVectorMemOps;
-    assert (NumSrcVecs > 1 && "Expected at least two source vectors.");
     NumPermutes += (NumDstVecs * NumSrcVecs) - NumDstVecs;
   }
 
diff --git a/llvm/test/Transforms/LoopVectorize/SystemZ/mem-interleaving-costs-03.ll b/llvm/test/Transforms/LoopVectorize/SystemZ/mem-interleaving-costs-03.ll
new file mode 100644
index 00000000000000..88eb9c4d27e33a
--- /dev/null
+++ b/llvm/test/Transforms/LoopVectorize/SystemZ/mem-interleaving-costs-03.ll
@@ -0,0 +1,42 @@
+; REQUIRES: asserts
+; RUN: opt -mtriple=s390x-unknown-linux -mcpu=z16 -passes=loop-vectorize \
+; RUN:   -debug-only=loop-vectorize -force-vector-width=4 \
+; RUN:   -disable-output < %s 2>&1 | FileCheck %s
+;
+; Check cost function for <8 x i128> store interleave group.
+
+; CHECK: LV: Checking a loop in 'fun'
+; CHECK: LV: Found an estimated cost of 8 for VF 4 For instruction:   store i128 8721036757475490113
+
+define noundef i32 @fun(i32 %argc, ptr nocapture readnone %argv) {
+entry:
+  %l_4774.i = alloca [4 x [2 x i128]], align 8
+  call void @llvm.lifetime.start.p0(i64 128, ptr nonnull %l_4774.i)
+  br label %for.cond4.preheader.i
+
+for.cond4.preheader.i:                            ; preds = %for.cond4.preheader.i, %entry
+  %indvars.iv8.i = phi i64 [ 0, %entry ], [ %indvars.iv.next9.i, %for.cond4.preheader.i ]
+  %arrayidx10.i = getelementptr inbounds [4 x [2 x i128]], ptr %l_4774.i, i64 0, i64 %indvars.iv8.i, i64 0
+  store i128 8721036757475490113, ptr %arrayidx10.i, align 8
+  %arrayidx10.i.c = getelementptr inbounds [4 x [2 x i128]], ptr %l_4774.i, i64 0, i64 %indvars.iv8.i, i64 1
+  store i128 8721036757475490113, ptr %arrayidx10.i.c, align 8
+  %indvars.iv.next9.i = add nuw nsw i64 %indvars.iv8.i, 1
+  %exitcond.not.i = icmp eq i64 %indvars.iv.next9.i, 4
+  br i1 %exitcond.not.i, label %func_1.exit, label %for.cond4.preheader.i
+
+func_1.exit:                                      ; preds = %for.cond4.preheader.i
+  %arrayidx195.i = getelementptr inbounds [4 x [2 x i128]], ptr %l_4774.i, i64 0, i64 1
+  %0 = load i128, ptr %arrayidx195.i, align 8
+  %cmp200.i = icmp ne i128 %0, 0
+  %conv202.i = zext i1 %cmp200.i to i64
+  %call203.i = tail call i64 @safe_sub_func_int64_t_s_s(i64 noundef %conv202.i, i64 noundef 9139899272418802852)
+  call void @llvm.lifetime.end.p0(i64 128, ptr nonnull %l_4774.i)
+  br label %for.cond
+
+for.cond:                                         ; preds = %for.cond, %func_1.exit
+  br label %for.cond
+}
+
+declare void @llvm.lifetime.start.p0(i64, ptr nocapture)
+declare void @llvm.lifetime.end.p0(i64, ptr nocapture)
+declare dso_local i64 @safe_sub_func_int64_t_s_s(i64, i64)

[uweigand]

LGTM