[llvm] ab736a2 - [BasicTTI] Account for vector of pointers in getMemoryOpCost

Philip Reames via llvm-commits llvm-commits at lists.llvm.org
Sat Jun 25 11:17:22 PDT 2022 

Author: Philip Reames
Date: 2022-06-25T11:11:58-07:00
New Revision: ab736a2750a99b303f8d6a216f754fb3577abb88

URL: https://github.com/llvm/llvm-project/commit/ab736a2750a99b303f8d6a216f754fb3577abb88
DIFF: https://github.com/llvm/llvm-project/commit/ab736a2750a99b303f8d6a216f754fb3577abb88.diff

LOG: [BasicTTI] Account for vector of pointers in getMemoryOpCost

By using getPrimitiveSizeInBits, we were getting 0 for every pointer type. This code is trying to account for the cost of truncating a store or extending a load to convert from the source vector element type to the legal vector element type.

I'd originally seen this as a crash when trying to scalarize a <vscale x 1 x ptr> type coming from the vectorizer. Here's a minimum reproducer to exercise the code in question.

void e(int *argv[], int *p) {
  for (int i = 0; i < 1024; i++)
    argv[i] = p;
}

This was checked in as the splat_ptr test in 2cf320d. After bbf3fd, this no longer crashes since we correctly return invalid if the extending load/truncating store isn't legal.

Differential Revision: https://reviews.llvm.org/D128228

Added: 
    

Modified: 
    llvm/include/llvm/CodeGen/BasicTTIImpl.h
    llvm/test/Analysis/CostModel/RISCV/rvv-load-store.ll

Removed: 
    


################################################################################
diff  --git a/llvm/include/llvm/CodeGen/BasicTTIImpl.h b/llvm/include/llvm/CodeGen/BasicTTIImpl.h
index 98cb4ebda8cf4..2ed687362cabd 100644
--- a/llvm/include/llvm/CodeGen/BasicTTIImpl.h
+++ b/llvm/include/llvm/CodeGen/BasicTTIImpl.h
@@ -1207,7 +1207,7 @@ class BasicTTIImplBase : public TargetTransformInfoImplCRTPBase<T> {
         // In practice it's not currently possible to have a change in lane
         // length for extending loads or truncating stores so both types should
         // have the same scalable property.
-        TypeSize::isKnownLT(Src->getPrimitiveSizeInBits(),
+        TypeSize::isKnownLT(DL.getTypeStoreSizeInBits(Src),
                             LT.second.getSizeInBits())) {
       // This is a vector load that legalizes to a larger type than the vector
       // itself. Unless the corresponding extending load or truncating store is

diff  --git a/llvm/test/Analysis/CostModel/RISCV/rvv-load-store.ll b/llvm/test/Analysis/CostModel/RISCV/rvv-load-store.ll
index e12a55e4eadf0..0a3135b78a851 100644
--- a/llvm/test/Analysis/CostModel/RISCV/rvv-load-store.ll
+++ b/llvm/test/Analysis/CostModel/RISCV/rvv-load-store.ll
@@ -58,16 +58,16 @@ define void @load(ptr %p) {
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %51 = load <vscale x 16 x i64>, ptr %p, align 128
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 4 for instruction: %52 = load <vscale x 32 x i64>, ptr %p, align 256
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %53 = load ptr, ptr %p, align 8
-; CHECK-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %54 = load <1 x ptr>, ptr %p, align 8
-; CHECK-NEXT:  Cost Model: Found an estimated cost of 3 for instruction: %55 = load <2 x ptr>, ptr %p, align 16
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %54 = load <1 x ptr>, ptr %p, align 8
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %55 = load <2 x ptr>, ptr %p, align 16
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %56 = load <4 x ptr>, ptr %p, align 32
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 4 for instruction: %57 = load <8 x ptr>, ptr %p, align 64
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 8 for instruction: %58 = load <16 x ptr>, ptr %p, align 128
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 16 for instruction: %59 = load <32 x ptr>, ptr %p, align 256
-; CHECK-NEXT:  Cost Model: Invalid cost for instruction: %60 = load <vscale x 1 x ptr>, ptr %p, align 8
-; CHECK-NEXT:  Cost Model: Invalid cost for instruction: %61 = load <vscale x 2 x ptr>, ptr %p, align 16
-; CHECK-NEXT:  Cost Model: Invalid cost for instruction: %62 = load <vscale x 4 x ptr>, ptr %p, align 32
-; CHECK-NEXT:  Cost Model: Invalid cost for instruction: %63 = load <vscale x 8 x ptr>, ptr %p, align 64
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %60 = load <vscale x 1 x ptr>, ptr %p, align 8
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %61 = load <vscale x 2 x ptr>, ptr %p, align 16
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %62 = load <vscale x 4 x ptr>, ptr %p, align 32
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: %63 = load <vscale x 8 x ptr>, ptr %p, align 64
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: %64 = load <vscale x 16 x ptr>, ptr %p, align 128
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 4 for instruction: %65 = load <vscale x 32 x ptr>, ptr %p, align 256
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: ret void
@@ -201,18 +201,18 @@ define void @store(ptr %p) {
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: store <vscale x 16 x i64> undef, ptr %p, align 128
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 4 for instruction: store <vscale x 32 x i64> undef, ptr %p, align 256
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: store ptr undef, ptr %p, align 8
-; CHECK-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: store <1 x ptr> undef, ptr %p, align 8
-; CHECK-NEXT:  Cost Model: Found an estimated cost of 3 for instruction: store <2 x ptr> undef, ptr %p, align 16
-; CHECK-NEXT:  Cost Model: Found an estimated cost of 6 for instruction: store <4 x ptr> undef, ptr %p, align 32
-; CHECK-NEXT:  Cost Model: Found an estimated cost of 12 for instruction: store <8 x ptr> undef, ptr %p, align 64
-; CHECK-NEXT:  Cost Model: Found an estimated cost of 24 for instruction: store <16 x ptr> undef, ptr %p, align 128
-; CHECK-NEXT:  Cost Model: Found an estimated cost of 48 for instruction: store <32 x ptr> undef, ptr %p, align 256
-; CHECK-NEXT:  Cost Model: Invalid cost for instruction: store <vscale x 1 x ptr> undef, ptr %p, align 8
-; CHECK-NEXT:  Cost Model: Invalid cost for instruction: store <vscale x 2 x ptr> undef, ptr %p, align 16
-; CHECK-NEXT:  Cost Model: Invalid cost for instruction: store <vscale x 4 x ptr> undef, ptr %p, align 32
-; CHECK-NEXT:  Cost Model: Invalid cost for instruction: store <vscale x 8 x ptr> undef, ptr %p, align 64
-; CHECK-NEXT:  Cost Model: Invalid cost for instruction: store <vscale x 16 x ptr> undef, ptr %p, align 128
-; CHECK-NEXT:  Cost Model: Invalid cost for instruction: store <vscale x 32 x ptr> undef, ptr %p, align 256
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: store <1 x ptr> undef, ptr %p, align 8
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: store <2 x ptr> undef, ptr %p, align 16
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: store <4 x ptr> undef, ptr %p, align 32
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 4 for instruction: store <8 x ptr> undef, ptr %p, align 64
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 8 for instruction: store <16 x ptr> undef, ptr %p, align 128
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 16 for instruction: store <32 x ptr> undef, ptr %p, align 256
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: store <vscale x 1 x ptr> undef, ptr %p, align 8
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: store <vscale x 2 x ptr> undef, ptr %p, align 16
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: store <vscale x 4 x ptr> undef, ptr %p, align 32
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: store <vscale x 8 x ptr> undef, ptr %p, align 64
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 2 for instruction: store <vscale x 16 x ptr> undef, ptr %p, align 128
+; CHECK-NEXT:  Cost Model: Found an estimated cost of 4 for instruction: store <vscale x 32 x ptr> undef, ptr %p, align 256
 ; CHECK-NEXT:  Cost Model: Found an estimated cost of 1 for instruction: ret void
 ;
   store i8 undef, ptr %p

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