[PATCH] D147040: [AArch64][CodeGen] Use interleave store for streaming compatible functions

[Caroline via Phabricator via llvm-commits]

CarolineConcatto created this revision.
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The previous patch, D135564 <https://reviews.llvm.org/D135564>, was too conservative to avoid store interleave
for streaming-compatible functions/mode.

In this patch, we allow using the interleave store but using scalable vector.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D147040

Files:
  llvm/lib/Target/AArch64/AArch64ISelLowering.cpp
  llvm/test/CodeGen/AArch64/sve-streaming-mode-fixed-length-shuffle.ll


Index: llvm/test/CodeGen/AArch64/sve-streaming-mode-fixed-length-shuffle.ll
===================================================================
--- llvm/test/CodeGen/AArch64/sve-streaming-mode-fixed-length-shuffle.ll
+++ llvm/test/CodeGen/AArch64/sve-streaming-mode-fixed-length-shuffle.ll
@@ -3,16 +3,14 @@
 
 target triple = "aarch64-unknown-linux-gnu"
 
-; Currently there is no custom lowering for vector shuffles operating on types
-; bigger than NEON. However, having no support opens us up to a code generator
-; hang when expanding BUILD_VECTOR. Here we just validate the promblematic case
-; successfully exits code generation.
 define void @hang_when_merging_stores_after_legalisation(ptr %a, <2 x i32> %b) #0 {
 ; CHECK-LABEL: hang_when_merging_stores_after_legalisation:
 ; CHECK:       // %bb.0:
 ; CHECK-NEXT:    // kill: def $d0 killed $d0 def $z0
+; CHECK-NEXT:    ptrue p0.s, vl4
 ; CHECK-NEXT:    mov z0.s, s0
-; CHECK-NEXT:    stp q0, q0, [x0]
+; CHECK-NEXT:    mov z1.d, z0.d
+; CHECK-NEXT:    st2w { z0.s, z1.s }, p0, [x0]
 ; CHECK-NEXT:    ret
   %splat = shufflevector <2 x i32> %b, <2 x i32> undef, <8 x i32> zeroinitializer
   %interleaved.vec = shufflevector <8 x i32> %splat, <8 x i32> undef, <8 x i32> <i32 0, i32 4, i32 1, i32 5, i32 2, i32 6, i32 3, i32 7>
Index: llvm/lib/Target/AArch64/AArch64ISelLowering.cpp
===================================================================
--- llvm/lib/Target/AArch64/AArch64ISelLowering.cpp
+++ llvm/lib/Target/AArch64/AArch64ISelLowering.cpp
@@ -14500,10 +14500,6 @@
 bool AArch64TargetLowering::lowerInterleavedStore(StoreInst *SI,
                                                   ShuffleVectorInst *SVI,
                                                   unsigned Factor) const {
-  // Skip if streaming compatible SVE is enabled, because it generates invalid
-  // code in streaming mode when SVE length is not specified.
-  if (Subtarget->forceStreamingCompatibleSVE())
-    return false;
 
   assert(Factor >= 2 && Factor <= getMaxSupportedInterleaveFactor() &&
          "Invalid interleave factor");
@@ -14517,6 +14513,8 @@
 
   const DataLayout &DL = SI->getModule()->getDataLayout();
   bool UseScalable;
+  if (Subtarget->forceStreamingCompatibleSVE())
+    UseScalable = true;
 
   // Skip if we do not have NEON and skip illegal vector types. We can
   // "legalize" wide vector types into multiple interleaved accesses as long as


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