[WebAssembly] Constant fold wasm.dot #149619
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@llvm/pr-subscribers-llvm-analysis Author: Jasmine Tang (badumbatish) ChangesConstant fold wasm.dot of constant vectors/splats. Test case added in Full diff: https://github.com/llvm/llvm-project/pull/149619.diff 2 Files Affected:
diff --git a/llvm/lib/Analysis/ConstantFolding.cpp b/llvm/lib/Analysis/ConstantFolding.cpp
index 9c1c2c6e60f02..2304c58b3f95f 100644
--- a/llvm/lib/Analysis/ConstantFolding.cpp
+++ b/llvm/lib/Analysis/ConstantFolding.cpp
@@ -1657,6 +1657,7 @@ bool llvm::canConstantFoldCallTo(const CallBase *Call, const Function *F) {
case Intrinsic::aarch64_sve_convert_from_svbool:
case Intrinsic::wasm_alltrue:
case Intrinsic::wasm_anytrue:
+ case Intrinsic::wasm_dot:
// WebAssembly float semantics are always known
case Intrinsic::wasm_trunc_signed:
case Intrinsic::wasm_trunc_unsigned:
@@ -3826,6 +3827,36 @@ static Constant *ConstantFoldFixedVectorCall(
}
return ConstantVector::get(Result);
}
+ case Intrinsic::wasm_dot: {
+ unsigned NumElements =
+ cast<FixedVectorType>(Operands[0]->getType())->getNumElements();
+
+ assert(NumElements == 8 && NumElements / 2 == Result.size() &&
+ "wasm dot takes i16x8 and produce i32x4");
+ assert(Ty->isIntegerTy());
+ SmallVector<APInt, 8> MulVector;
+
+ for (unsigned I = 0; I < NumElements; ++I) {
+ ConstantInt *Elt0 =
+ cast<ConstantInt>(Operands[0]->getAggregateElement(I));
+ ConstantInt *Elt1 =
+ cast<ConstantInt>(Operands[1]->getAggregateElement(I));
+
+ // sext 32 first, according to specs
+ APInt IMul = Elt0->getValue().sext(32) * Elt1->getValue().sext(32);
+
+ // TODO: imul in specs includes a modulo operation
+ // Is this performed automatically via trunc = true in APInt creation of *
+ MulVector.push_back(IMul);
+ }
+ for (unsigned I = 0; I < Result.size(); ++I) {
+ // Same case as with imul
+ APInt IAdd = MulVector[I] + MulVector[I + Result.size()];
+ Result[I] = ConstantInt::get(Ty, IAdd);
+ }
+
+ return ConstantVector::get(Result);
+ }
default:
break;
}
diff --git a/llvm/test/Transforms/InstSimplify/ConstProp/WebAssembly/dot.ll b/llvm/test/Transforms/InstSimplify/ConstProp/WebAssembly/dot.ll
new file mode 100644
index 0000000000000..02c6649becbce
--- /dev/null
+++ b/llvm/test/Transforms/InstSimplify/ConstProp/WebAssembly/dot.ll
@@ -0,0 +1,39 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 5
+
+; RUN: opt -passes=instsimplify -S < %s | FileCheck %s
+
+; Test that intrinsics wasm dot call are constant folded
+
+target triple = "wasm32-unknown-unknown"
+
+
+define <4 x i32> @dot_zero() {
+; CHECK-LABEL: define <4 x i32> @dot_zero() {
+; CHECK-NEXT: ret <4 x i32> zeroinitializer
+;
+ %res = tail call <4 x i32> @llvm.wasm.dot(<8 x i16> zeroinitializer, <8 x i16> zeroinitializer)
+ ret <4 x i32> %res
+}
+
+; a = 1 2 3 4 5 6 7 8
+; b = 1 2 3 4 5 6 7 8
+; k1|k2 = a * b = 1 4 9 16 25 36 49 64
+; k1 + k2 = (1+25) | (4+36) | (9+49) | (16+64)
+; result = 26 | 40 | 58 | 80
+define <4 x i32> @dot_nonzero() {
+; CHECK-LABEL: define <4 x i32> @dot_nonzero() {
+; CHECK-NEXT: ret <4 x i32> <i32 26, i32 40, i32 58, i32 80>
+;
+ %res = tail call <4 x i32> @llvm.wasm.dot(<8 x i16> <i16 1, i16 2, i16 3, i16 4, i16 5, i16 6, i16 7, i16 8>, <8 x i16> <i16 1, i16 2, i16 3, i16 4, i16 5, i16 6, i16 7, i16 8>)
+ ret <4 x i32> %res
+}
+
+define <4 x i32> @dot_doubly_negative() {
+; CHECK-LABEL: define <4 x i32> @dot_doubly_negative() {
+; CHECK-NEXT: ret <4 x i32> splat (i32 2)
+;
+ %res = tail call <4 x i32> @llvm.wasm.dot(<8 x i16> <i16 -1, i16 -1, i16 -1, i16 -1, i16 -1, i16 -1, i16 -1, i16 -1>, <8 x i16> <i16 -1, i16 -1, i16 -1, i16 -1, i16 -1, i16 -1, i16 -1, i16 -1>)
+ ret <4 x i32> %res
+}
+
+
|
|
@llvm/pr-subscribers-llvm-transforms Author: Jasmine Tang (badumbatish) ChangesConstant fold wasm.dot of constant vectors/splats. Test case added in Full diff: https://github.com/llvm/llvm-project/pull/149619.diff 2 Files Affected:
diff --git a/llvm/lib/Analysis/ConstantFolding.cpp b/llvm/lib/Analysis/ConstantFolding.cpp
index 9c1c2c6e60f02..2304c58b3f95f 100644
--- a/llvm/lib/Analysis/ConstantFolding.cpp
+++ b/llvm/lib/Analysis/ConstantFolding.cpp
@@ -1657,6 +1657,7 @@ bool llvm::canConstantFoldCallTo(const CallBase *Call, const Function *F) {
case Intrinsic::aarch64_sve_convert_from_svbool:
case Intrinsic::wasm_alltrue:
case Intrinsic::wasm_anytrue:
+ case Intrinsic::wasm_dot:
// WebAssembly float semantics are always known
case Intrinsic::wasm_trunc_signed:
case Intrinsic::wasm_trunc_unsigned:
@@ -3826,6 +3827,36 @@ static Constant *ConstantFoldFixedVectorCall(
}
return ConstantVector::get(Result);
}
+ case Intrinsic::wasm_dot: {
+ unsigned NumElements =
+ cast<FixedVectorType>(Operands[0]->getType())->getNumElements();
+
+ assert(NumElements == 8 && NumElements / 2 == Result.size() &&
+ "wasm dot takes i16x8 and produce i32x4");
+ assert(Ty->isIntegerTy());
+ SmallVector<APInt, 8> MulVector;
+
+ for (unsigned I = 0; I < NumElements; ++I) {
+ ConstantInt *Elt0 =
+ cast<ConstantInt>(Operands[0]->getAggregateElement(I));
+ ConstantInt *Elt1 =
+ cast<ConstantInt>(Operands[1]->getAggregateElement(I));
+
+ // sext 32 first, according to specs
+ APInt IMul = Elt0->getValue().sext(32) * Elt1->getValue().sext(32);
+
+ // TODO: imul in specs includes a modulo operation
+ // Is this performed automatically via trunc = true in APInt creation of *
+ MulVector.push_back(IMul);
+ }
+ for (unsigned I = 0; I < Result.size(); ++I) {
+ // Same case as with imul
+ APInt IAdd = MulVector[I] + MulVector[I + Result.size()];
+ Result[I] = ConstantInt::get(Ty, IAdd);
+ }
+
+ return ConstantVector::get(Result);
+ }
default:
break;
}
diff --git a/llvm/test/Transforms/InstSimplify/ConstProp/WebAssembly/dot.ll b/llvm/test/Transforms/InstSimplify/ConstProp/WebAssembly/dot.ll
new file mode 100644
index 0000000000000..02c6649becbce
--- /dev/null
+++ b/llvm/test/Transforms/InstSimplify/ConstProp/WebAssembly/dot.ll
@@ -0,0 +1,39 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 5
+
+; RUN: opt -passes=instsimplify -S < %s | FileCheck %s
+
+; Test that intrinsics wasm dot call are constant folded
+
+target triple = "wasm32-unknown-unknown"
+
+
+define <4 x i32> @dot_zero() {
+; CHECK-LABEL: define <4 x i32> @dot_zero() {
+; CHECK-NEXT: ret <4 x i32> zeroinitializer
+;
+ %res = tail call <4 x i32> @llvm.wasm.dot(<8 x i16> zeroinitializer, <8 x i16> zeroinitializer)
+ ret <4 x i32> %res
+}
+
+; a = 1 2 3 4 5 6 7 8
+; b = 1 2 3 4 5 6 7 8
+; k1|k2 = a * b = 1 4 9 16 25 36 49 64
+; k1 + k2 = (1+25) | (4+36) | (9+49) | (16+64)
+; result = 26 | 40 | 58 | 80
+define <4 x i32> @dot_nonzero() {
+; CHECK-LABEL: define <4 x i32> @dot_nonzero() {
+; CHECK-NEXT: ret <4 x i32> <i32 26, i32 40, i32 58, i32 80>
+;
+ %res = tail call <4 x i32> @llvm.wasm.dot(<8 x i16> <i16 1, i16 2, i16 3, i16 4, i16 5, i16 6, i16 7, i16 8>, <8 x i16> <i16 1, i16 2, i16 3, i16 4, i16 5, i16 6, i16 7, i16 8>)
+ ret <4 x i32> %res
+}
+
+define <4 x i32> @dot_doubly_negative() {
+; CHECK-LABEL: define <4 x i32> @dot_doubly_negative() {
+; CHECK-NEXT: ret <4 x i32> splat (i32 2)
+;
+ %res = tail call <4 x i32> @llvm.wasm.dot(<8 x i16> <i16 -1, i16 -1, i16 -1, i16 -1, i16 -1, i16 -1, i16 -1, i16 -1>, <8 x i16> <i16 -1, i16 -1, i16 -1, i16 -1, i16 -1, i16 -1, i16 -1, i16 -1>)
+ ret <4 x i32> %res
+}
+
+
|
tlively
reviewed
Jul 21, 2025
lukel97
reviewed
Jul 28, 2025
lukel97
reviewed
Aug 4, 2025
|
thanks everyone, just need an approve check and i'll merge it |
tlively
approved these changes
Aug 5, 2025
|
LLVM Buildbot has detected a new failure on builder Full details are available at: https://lab.llvm.org/buildbot/#/builders/10/builds/10927 Here is the relevant piece of the build log for the reference |
|
It breaks ubsan bot: Earlier today the failure was hidden by another breakage that is fixed now. |
alazarev
added a commit
to alazarev/llvm-project
that referenced
this pull request
Aug 6, 2025
This reverts commit 9c6bb18.
bjope
reviewed
Aug 6, 2025
| MulVector[I] = Elt0->getSExtValue() * Elt1->getSExtValue(); | ||
| } | ||
| for (unsigned I = 0; I < Result.size(); I++) { | ||
| int32_t IAdd = MulVector[I * 2] + MulVector[I * 2 + 1]; |
There was a problem hiding this comment.
When building opt with ubsan this result in runtime errors when running the new dot.ll test:
../lib/Analysis/ConstantFolding.cpp:4011:39: runtime error: signed integer overflow: 1073741824 + 1073741824 cannot be represented in type 'int32_t' (aka 'int')
SUMMARY: UndefinedBehaviorSanitizer: undefined-behavior ../lib/Analysis/ConstantFolding.cpp:4011:39
PS. The line numbers in the pull request does not match the final line numbers in the commit, but line 4011 in the output above seems to match with this line.
vitalybuka
pushed a commit
that referenced
this pull request
Aug 6, 2025
Reverts #149619 It breaks ubsan bot: https://lab.llvm.org/buildbot/#/builders/25/builds/10523 Earlier today the failure was hidden by another breakage that is fixed now.
|
Reverted here #152382 |
|
thanks Vitaly, sorry about that, will try to redo the pr |
llvm-sync bot
pushed a commit
to arm/arm-toolchain
that referenced
this pull request
Aug 6, 2025
Reverts llvm/llvm-project#149619 It breaks ubsan bot: https://lab.llvm.org/buildbot/#/builders/25/builds/10523 Earlier today the failure was hidden by another breakage that is fixed now.
krishna2803
pushed a commit
to krishna2803/llvm-project
that referenced
this pull request
Aug 12, 2025
Constant fold wasm.dot of constant vectors/splats. Test case added in `llvm/test/Transforms/InstSimplify/ConstProp/WebAssembly/dot.ll` Related to llvm#55933
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Constant fold wasm.dot of constant vectors/splats.
Test case added in
llvm/test/Transforms/InstSimplify/ConstProp/WebAssembly/dot.llRelated to #55933