[llvm] e620eac - [SelectionDAG][RISCV][SVE] Harden fixed offset version of ComputeValueVTs against scalable offsets.

[Craig Topper via llvm-commits]

Author: Craig Topper
Date: 2023-08-21T10:36:17-07:00
New Revision: e620eac75e470f94928a17d215a3be947712028b

URL: https://github.com/llvm/llvm-project/commit/e620eac75e470f94928a17d215a3be947712028b
DIFF: https://github.com/llvm/llvm-project/commit/e620eac75e470f94928a17d215a3be947712028b.diff

LOG: [SelectionDAG][RISCV][SVE] Harden fixed offset version of ComputeValueVTs against scalable offsets.

Use getFixedValue instead of getKnownMinValue to convert TypeSize
to uint64_t. I believe this would have caught the bug fixed by
D157872.

To prevent false failures, I had to treat a scalable 0 as if it
is fixed value.

Reviewed By: paulwalker-arm

Differential Revision: https://reviews.llvm.org/D158115

Added: 
    

Modified: 
    llvm/include/llvm/Support/TypeSize.h
    llvm/lib/CodeGen/Analysis.cpp

Removed: 
    


################################################################################
diff  --git a/llvm/include/llvm/Support/TypeSize.h b/llvm/include/llvm/Support/TypeSize.h
index 9683c82b2278fe..5c15ed9e4d9bdf 100644
--- a/llvm/include/llvm/Support/TypeSize.h
+++ b/llvm/include/llvm/Support/TypeSize.h
@@ -180,7 +180,7 @@ template <typename LeafTy, typename ValueTy> class FixedOrScalableQuantity {
   // Use in places where a scalable count doesn't make sense (e.g. non-vector
   // types, or vectors in backends which don't support scalable vectors).
   constexpr ScalarTy getFixedValue() const {
-    assert(!isScalable() &&
+    assert((!isScalable() || isZero()) &&
            "Request for a fixed element count on a scalable object");
     return getKnownMinValue();
   }

diff  --git a/llvm/lib/CodeGen/Analysis.cpp b/llvm/lib/CodeGen/Analysis.cpp
index 2065bfbd1c4499..1994e6aec84b23 100644
--- a/llvm/lib/CodeGen/Analysis.cpp
+++ b/llvm/lib/CodeGen/Analysis.cpp
@@ -140,15 +140,14 @@ void llvm::ComputeValueVTs(const TargetLowering &TLI, const DataLayout &DL,
                            SmallVectorImpl<uint64_t> *FixedOffsets,
                            uint64_t StartingOffset) {
   TypeSize Offset = TypeSize::get(StartingOffset, Ty->isScalableTy());
-  SmallVector<TypeSize, 4> Offsets;
-  if (FixedOffsets)
+  if (FixedOffsets) {
+    SmallVector<TypeSize, 4> Offsets;
     ComputeValueVTs(TLI, DL, Ty, ValueVTs, &Offsets, Offset);
-  else
-    ComputeValueVTs(TLI, DL, Ty, ValueVTs, nullptr, Offset);
-
-  if (FixedOffsets)
     for (TypeSize Offset : Offsets)
-      FixedOffsets->push_back(Offset.getKnownMinValue());
+      FixedOffsets->push_back(Offset.getFixedValue());
+  } else {
+    ComputeValueVTs(TLI, DL, Ty, ValueVTs, nullptr, Offset);
+  }
 }
 
 void llvm::ComputeValueVTs(const TargetLowering &TLI, const DataLayout &DL,
@@ -166,15 +165,14 @@ void llvm::ComputeValueVTs(const TargetLowering &TLI, const DataLayout &DL,
                            SmallVectorImpl<uint64_t> *FixedOffsets,
                            uint64_t StartingOffset) {
   TypeSize Offset = TypeSize::get(StartingOffset, Ty->isScalableTy());
-  SmallVector<TypeSize, 4> Offsets;
-  if (FixedOffsets)
+  if (FixedOffsets) {
+    SmallVector<TypeSize, 4> Offsets;
     ComputeValueVTs(TLI, DL, Ty, ValueVTs, MemVTs, &Offsets, Offset);
-  else
-    ComputeValueVTs(TLI, DL, Ty, ValueVTs, MemVTs, nullptr, Offset);
-
-  if (FixedOffsets)
     for (TypeSize Offset : Offsets)
-      FixedOffsets->push_back(Offset.getKnownMinValue());
+      FixedOffsets->push_back(Offset.getFixedValue());
+  } else {
+    ComputeValueVTs(TLI, DL, Ty, ValueVTs, MemVTs, nullptr, Offset);
+  }
 }
 
 void llvm::computeValueLLTs(const DataLayout &DL, Type &Ty,