[llvm] [InferAddressSpaces] Handle unconverted ptrmask (PR #140802)
Robert Imschweiler via llvm-commits
llvm-commits at lists.llvm.org
Wed May 21 01:43:14 PDT 2025
https://github.com/ro-i updated https://github.com/llvm/llvm-project/pull/140802
>From 7e2f064c3323933a18f1f71e3bc998fcce90cd4a Mon Sep 17 00:00:00 2001
From: Robert Imschweiler <robert.imschweiler at amd.com>
Date: Tue, 20 May 2025 15:55:36 -0500
Subject: [PATCH 1/2] [InferAddressSpaces] Handle unconverted ptrmask
In case a ptrmask cannot be converted to the new address space due to an
unknown mask value, this needs to be detcted and an addrspacecast is
needed to not hinder a future use of the unconverted return value of
ptrmask. Otherwise, users of this value will become invalid by receiving
a nullptr as an operand.
This LLVM defect was identified via the AMD Fuzzing project.
---
.../Transforms/Scalar/InferAddressSpaces.cpp | 15 ++++++++++++++-
.../InferAddressSpaces/AMDGPU/ptrmask.ll | 18 ++++++++++++++++++
2 files changed, 32 insertions(+), 1 deletion(-)
diff --git a/llvm/lib/Transforms/Scalar/InferAddressSpaces.cpp b/llvm/lib/Transforms/Scalar/InferAddressSpaces.cpp
index d3771c0903456..4f2e8bbd1102a 100644
--- a/llvm/lib/Transforms/Scalar/InferAddressSpaces.cpp
+++ b/llvm/lib/Transforms/Scalar/InferAddressSpaces.cpp
@@ -1338,7 +1338,20 @@ bool InferAddressSpacesImpl::rewriteWithNewAddressSpaces(
unsigned OperandNo = PoisonUse->getOperandNo();
assert(isa<PoisonValue>(NewV->getOperand(OperandNo)));
- NewV->setOperand(OperandNo, ValueWithNewAddrSpace.lookup(PoisonUse->get()));
+ WeakTrackingVH NewOp = ValueWithNewAddrSpace.lookup(PoisonUse->get());
+ if (NewOp) {
+ NewV->setOperand(OperandNo, NewOp);
+ } else {
+ // Something went wrong while converting the instruction defining the new
+ // operand value. -> Replace the poison value with the previous operand
+ // value combined with an addrspace case.
+ Value *PoisonOp = NewV->getOperand(OperandNo);
+ Value *OldOp = V->getOperand(OperandNo);
+ Value *AddrSpaceCast =
+ new AddrSpaceCastInst(OldOp, PoisonOp->getType(), "",
+ cast<Instruction>(NewV)->getIterator());
+ NewV->setOperand(OperandNo, AddrSpaceCast);
+ }
}
SmallVector<Instruction *, 16> DeadInstructions;
diff --git a/llvm/test/Transforms/InferAddressSpaces/AMDGPU/ptrmask.ll b/llvm/test/Transforms/InferAddressSpaces/AMDGPU/ptrmask.ll
index 6ef926f935830..1c1d1df79520d 100644
--- a/llvm/test/Transforms/InferAddressSpaces/AMDGPU/ptrmask.ll
+++ b/llvm/test/Transforms/InferAddressSpaces/AMDGPU/ptrmask.ll
@@ -343,6 +343,24 @@ define i8 @ptrmask_cast_local_to_flat_load_range_mask(ptr addrspace(3) %src.ptr,
ret i8 %load
}
+; Non-const masks with no known range should not prevent other ptr-manipulating
+; instructions (such as gep) from being converted.
+define i8 @ptrmask_cast_local_to_flat_unknown_mask(ptr addrspace(3) %src.ptr, i64 %mask, i64 %idx) {
+; CHECK-LABEL: @ptrmask_cast_local_to_flat_unknown_mask(
+; CHECK-NEXT: [[CAST:%.*]] = addrspacecast ptr addrspace(3) [[SRC_PTR:%.*]] to ptr
+; CHECK-NEXT: [[MASKED:%.*]] = call ptr @llvm.ptrmask.p0.i64(ptr [[CAST]], i64 [[MASK:%.*]])
+; CHECK-NEXT: [[TMP1:%.*]] = addrspacecast ptr [[MASKED]] to ptr addrspace(3)
+; CHECK-NEXT: [[GEP:%.*]] = getelementptr i8, ptr addrspace(3) [[TMP1]], i64 [[IDX:%.*]]
+; CHECK-NEXT: [[LOAD:%.*]] = load i8, ptr addrspace(3) [[GEP]], align 1
+; CHECK-NEXT: ret i8 [[LOAD]]
+;
+ %cast = addrspacecast ptr addrspace(3) %src.ptr to ptr
+ %masked = call ptr @llvm.ptrmask.p0.i64(ptr %cast, i64 %mask)
+ %gep = getelementptr i8, ptr %masked, i64 %idx
+ %load = load i8, ptr %gep
+ ret i8 %load
+}
+
declare ptr @llvm.ptrmask.p0.i64(ptr, i64) #0
declare ptr addrspace(5) @llvm.ptrmask.p5.i32(ptr addrspace(5), i32) #0
declare ptr addrspace(3) @llvm.ptrmask.p3.i32(ptr addrspace(3), i32) #0
>From 0d02438f6e135af394d67dedb18b12f19e38b397 Mon Sep 17 00:00:00 2001
From: Robert Imschweiler <robert.imschweiler at amd.com>
Date: Wed, 21 May 2025 03:42:35 -0500
Subject: [PATCH 2/2] implement feedback
---
.../Transforms/Scalar/InferAddressSpaces.cpp | 2 +-
.../InferAddressSpaces/AMDGPU/ptrmask.ll | 18 ++++++++++++++++++
2 files changed, 19 insertions(+), 1 deletion(-)
diff --git a/llvm/lib/Transforms/Scalar/InferAddressSpaces.cpp b/llvm/lib/Transforms/Scalar/InferAddressSpaces.cpp
index 4f2e8bbd1102a..3b05dd2bddcb3 100644
--- a/llvm/lib/Transforms/Scalar/InferAddressSpaces.cpp
+++ b/llvm/lib/Transforms/Scalar/InferAddressSpaces.cpp
@@ -1344,7 +1344,7 @@ bool InferAddressSpacesImpl::rewriteWithNewAddressSpaces(
} else {
// Something went wrong while converting the instruction defining the new
// operand value. -> Replace the poison value with the previous operand
- // value combined with an addrspace case.
+ // value combined with an addrspacecast.
Value *PoisonOp = NewV->getOperand(OperandNo);
Value *OldOp = V->getOperand(OperandNo);
Value *AddrSpaceCast =
diff --git a/llvm/test/Transforms/InferAddressSpaces/AMDGPU/ptrmask.ll b/llvm/test/Transforms/InferAddressSpaces/AMDGPU/ptrmask.ll
index 1c1d1df79520d..ccc7df89dcd8e 100644
--- a/llvm/test/Transforms/InferAddressSpaces/AMDGPU/ptrmask.ll
+++ b/llvm/test/Transforms/InferAddressSpaces/AMDGPU/ptrmask.ll
@@ -361,7 +361,25 @@ define i8 @ptrmask_cast_local_to_flat_unknown_mask(ptr addrspace(3) %src.ptr, i6
ret i8 %load
}
+define i8 @ptrmask_vector_cast_local_to_flat_unknown_mask(<2 x ptr addrspace(3)> %src.ptr, <2 x i64> %mask, i64 %ptridx, i64 %idx) {
+; CHECK-LABEL: @ptrmask_vector_cast_local_to_flat_unknown_mask(
+; CHECK-NEXT: [[CAST:%.*]] = addrspacecast <2 x ptr addrspace(3)> [[SRC_PTR:%.*]] to <2 x ptr>
+; CHECK-NEXT: [[MASKED:%.*]] = call <2 x ptr> @llvm.ptrmask.v2p0.v2i64(<2 x ptr> [[CAST]], <2 x i64> [[MASK:%.*]])
+; CHECK-NEXT: [[PTR:%.*]] = extractelement <2 x ptr> [[MASKED]], i64 [[PTRIDX:%.*]]
+; CHECK-NEXT: [[GEP:%.*]] = getelementptr i8, ptr [[PTR]], i64 [[IDX:%.*]]
+; CHECK-NEXT: [[LOAD:%.*]] = load i8, ptr [[GEP]], align 1
+; CHECK-NEXT: ret i8 [[LOAD]]
+;
+ %cast = addrspacecast <2 x ptr addrspace(3)> %src.ptr to <2 x ptr>
+ %masked = call <2 x ptr> @llvm.ptrmask.v2p0.v2i64(<2 x ptr> %cast, <2 x i64> %mask)
+ %ptr = extractelement <2 x ptr> %masked, i64 %ptridx
+ %gep = getelementptr i8, ptr %ptr, i64 %idx
+ %load = load i8, ptr %gep
+ ret i8 %load
+}
+
declare ptr @llvm.ptrmask.p0.i64(ptr, i64) #0
+declare <2 x ptr> @llvm.ptrmask.v2p0.v2i64(<2 x ptr>, <2 x i64>) #0
declare ptr addrspace(5) @llvm.ptrmask.p5.i32(ptr addrspace(5), i32) #0
declare ptr addrspace(3) @llvm.ptrmask.p3.i32(ptr addrspace(3), i32) #0
declare ptr addrspace(1) @llvm.ptrmask.p1.i64(ptr addrspace(1), i64) #0
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