[Mlir-commits] [mlir] [MLIR][TOSA-Linalg] Fix rescale lowering for unsigned input zp (PR #138313)
llvmlistbot at llvm.org
llvmlistbot at llvm.org
Fri May 2 10:54:15 PDT 2025
llvmbot wrote:
<!--LLVM PR SUMMARY COMMENT-->
@llvm/pr-subscribers-mlir
Author: Thomas Preud'homme (RoboTux)
<details>
<summary>Changes</summary>
Lowering of tosa.rescale to Linalg unconditionally sign-extend the input
zero-point value, even when unsigned_input is true. This commit refactor
zeropoint handling to share the same logic between input and output
zeropoint.
---
Full diff: https://github.com/llvm/llvm-project/pull/138313.diff
2 Files Affected:
- (modified) mlir/lib/Conversion/TosaToLinalg/TosaToLinalg.cpp (+18-26)
- (modified) mlir/test/Conversion/TosaToLinalg/tosa-to-linalg.mlir (+35-3)
``````````diff
diff --git a/mlir/lib/Conversion/TosaToLinalg/TosaToLinalg.cpp b/mlir/lib/Conversion/TosaToLinalg/TosaToLinalg.cpp
index 95364c26d1a7d..857f2721e1328 100644
--- a/mlir/lib/Conversion/TosaToLinalg/TosaToLinalg.cpp
+++ b/mlir/lib/Conversion/TosaToLinalg/TosaToLinalg.cpp
@@ -82,13 +82,16 @@ materializeBinaryNanCheckIfRequired(OpTy op, PatternRewriter &rewriter,
rhsOrResult);
}
-template <typename T>
+// Create i32 Value from zp, a zero-point value sign-extended from bitwidth.
static arith::ConstantOp
-createConstOpFromZpVal(Operation *op, const int64_t &zp, Type requiredAttrType,
- OpBuilder &rewriter) {
- auto castedN = static_cast<T>(zp);
+createConstOpFromSExtZp(int64_t zp, unsigned zpBitwidth, unsigned attrBitwidth,
+ bool isSigned, Location loc, OpBuilder &rewriter) {
+
+ // Zero the signed-extended bits if isSigned is false.
+ zp = isSigned ? zp : zp & ((1 << zpBitwidth) - 1);
+
return rewriter.create<arith::ConstantOp>(
- op->getLoc(), IntegerAttr::get(requiredAttrType, castedN));
+ loc, IntegerAttr::get(rewriter.getIntegerType(attrBitwidth), zp));
}
static Value createLinalgBodyCalculationForElementwiseOp(
@@ -1467,11 +1470,6 @@ class RescaleConverter : public OpRewritePattern<tosa::RescaleOp> {
Value value = blockArgs[0];
Type valueTy = value.getType();
- // For now we do all of our math in 64-bit. This is not optimal but
- // should be correct for now, consider computing correct bit depth
- // later.
- int32_t inBitwidth = valueTy.getIntOrFloatBitWidth() > 32 ? 48 : 32;
-
FailureOr<int64_t> maybeIZp = op.getInputZeroPoint();
if (failed(maybeIZp)) {
(void)rewriter.notifyMatchFailure(
@@ -1479,8 +1477,10 @@ class RescaleConverter : public OpRewritePattern<tosa::RescaleOp> {
return;
}
- auto inputZp = createConstOpFromZpVal<int32_t>(
- op, *maybeIZp, nestedBuilder.getIntegerType(inBitwidth),
+ const int32_t inBitwidth = valueTy.getIntOrFloatBitWidth();
+ const int32_t attrBitwidth = inBitwidth > 32 ? 48 : 32;
+ auto inputZp = createConstOpFromSExtZp(
+ *maybeIZp, inBitwidth, attrBitwidth, !op.getInputUnsigned(), loc,
nestedBuilder);
FailureOr<int64_t> maybeOZp = op.getOutputZeroPoint();
@@ -1490,16 +1490,12 @@ class RescaleConverter : public OpRewritePattern<tosa::RescaleOp> {
return;
};
- // pre-process OutputZP as it can be unsigned
- auto outBitwidth = outputTy.getElementType().getIntOrFloatBitWidth();
- APInt OZp(outBitwidth, !op.getOutputUnsigned());
- OZp = static_cast<int64_t>(*maybeOZp);
- *maybeOZp = op.getOutputUnsigned()
- ? static_cast<int64_t>(OZp.getZExtValue())
- : OZp.getSExtValue();
-
- auto outputZp = createConstOpFromZpVal<int32_t>(
- op, *maybeOZp, nestedBuilder.getI32Type(), nestedBuilder);
+ IntegerType outIntType =
+ cast<IntegerType>(blockArgs.back().getType());
+ unsigned outBitWidth = outIntType.getWidth();
+ auto outputZp = createConstOpFromSExtZp(
+ *maybeOZp, outBitWidth, /*attrBitwidth=*/32,
+ !op.getOutputUnsigned(), loc, nestedBuilder);
Value multiplier = multiplierConstant ? multiplierConstant
: blockArgs[multiplierArg];
@@ -1527,10 +1523,6 @@ class RescaleConverter : public OpRewritePattern<tosa::RescaleOp> {
nestedBuilder.create<arith::AddIOp>(nestedLoc, value, outputZp);
// Saturate to the output size.
- IntegerType outIntType =
- cast<IntegerType>(blockArgs.back().getType());
- unsigned outBitWidth = outIntType.getWidth();
-
int32_t intMin = APInt::getSignedMinValue(outBitWidth).getSExtValue();
int32_t intMax = APInt::getSignedMaxValue(outBitWidth).getSExtValue();
diff --git a/mlir/test/Conversion/TosaToLinalg/tosa-to-linalg.mlir b/mlir/test/Conversion/TosaToLinalg/tosa-to-linalg.mlir
index 7083d19f4372a..185f1973ecdc6 100644
--- a/mlir/test/Conversion/TosaToLinalg/tosa-to-linalg.mlir
+++ b/mlir/test/Conversion/TosaToLinalg/tosa-to-linalg.mlir
@@ -1241,10 +1241,10 @@ func.func @rescale_i8_unsigned_input(%arg0 : tensor<2xi8>) -> () {
// CHECK: [[INIT:%.+]] = tensor.empty()
// CHECK: [[GENERIC:%.+]] = linalg.generic {indexing_maps = [#[[$MAP0]], #[[$MAP0]]], iterator_types = ["parallel"]} ins(%[[ARG0]] : tensor<2xi8>) outs([[INIT]] : tensor<2xi8>)
// CHECK: ^bb0([[IN:%.+]]: i8, [[UNUSED:%.+]]: i8):
- // CHECK: [[C17:%.+]] = arith.constant 17
+ // CHECK: [[C128:%.+]] = arith.constant 128
// CHECK: [[C22:%.+]] = arith.constant 22
// CHECK-DAG: [[IN32:%.+]] = arith.extui [[IN]]
- // CHECK-DAG: [[IN_ZEROED:%.+]] = arith.subi [[IN32]], [[C17]]
+ // CHECK-DAG: [[IN_ZEROED:%.+]] = arith.subi [[IN32]], [[C128]]
// CHECK-DAG: [[SCALED:%.+]] = tosa.apply_scale [[IN_ZEROED]], [[C0]], [[C1]] {rounding_mode = "SINGLE_ROUND"}
// CHECK-DAG: [[SCALED_ZEROED:%.+]] = arith.addi [[SCALED]], [[C22]]
// CHECK-DAG: [[CMIN:%.+]] = arith.constant -128
@@ -1255,13 +1255,45 @@ func.func @rescale_i8_unsigned_input(%arg0 : tensor<2xi8>) -> () {
// CHECK: linalg.yield [[TRUNC]]
%multiplier = "tosa.const"() {values = dense<19689> : tensor<1xi16> } : () -> tensor<1xi16>
%shift = "tosa.const"() {values = dense<15> : tensor<1xi8> } : () -> tensor<1xi8>
- %input_zp = "tosa.const"() {values = dense<17> : tensor<1xi8>} : () -> tensor<1xi8>
+ %input_zp = "tosa.const"() {values = dense<-128> : tensor<1xi8>} : () -> tensor<1xi8>
%output_zp = "tosa.const"() {values = dense<22> : tensor<1xi8>} : () -> tensor<1xi8>
%0 = tosa.rescale %arg0, %multiplier, %shift, %input_zp, %output_zp {scale32 = false, rounding_mode = "SINGLE_ROUND", per_channel = false, input_unsigned = true, output_unsigned = false} : (tensor<2xi8>, tensor<1xi16>, tensor<1xi8>, tensor<1xi8>, tensor<1xi8>) -> tensor<2xi8>
return
}
+// -----
+// CHECK: #[[$MAP0:.*]] = affine_map<(d0) -> (d0)>
+
+// CHECK-LABEL: @rescale_i48_unsigned_output
+// CHECK-SAME: (%[[ARG0:[0-9a-zA-Z_]*]]:
+func.func @rescale_i48_unsigned_output(%arg0 : tensor<2xi48>) -> () {
+ // CHECK: [[C19689:%.+]] = arith.constant 19689
+ // CHECK: [[C15:%.+]] = arith.constant 15
+ // CHECK: [[INIT:%.+]] = tensor.empty()
+ // CHECK: [[GENERIC:%.+]] = linalg.generic {indexing_maps = [#[[$MAP0]], #[[$MAP0]]], iterator_types = ["parallel"]} ins(%[[ARG0]] : tensor<2xi48>) outs([[INIT]] : tensor<2xi8>)
+ // CHECK: ^bb0([[IN:%.+]]: i48, [[UNUSED:%.+]]: i8):
+ // CHECK: [[C0:%.+]] = arith.constant 0
+ // CHECK: [[C234:%.+]] = arith.constant 234
+ // CHECK-DAG: [[IN_ZEROED:%.+]] = arith.subi [[IN]], [[C0]]
+ // CHECK-DAG: [[SCALED:%.+]] = tosa.apply_scale [[IN_ZEROED]], [[C19689]], [[C15]] {rounding_mode = "SINGLE_ROUND"}
+ // CHECK-DAG: [[SCALED_ZEROED:%.+]] = arith.addi [[SCALED]], [[C234]]
+ // CHECK-DAG: [[CMIN:%.+]] = arith.constant 0
+ // CHECK-DAG: [[CMAX:%.+]] = arith.constant 255
+ // CHECK-DAG: [[LOWER:%.+]] = arith.maxsi [[CMIN]], [[SCALED_ZEROED]]
+ // CHECK-DAG: [[BOUNDED:%.+]] = arith.minsi [[CMAX]], [[LOWER]]
+ // CHECK-DAG: [[TRUNC:%.+]] = arith.trunci [[BOUNDED]]
+ // CHECK: linalg.yield [[TRUNC]]
+ %multiplier = "tosa.const"() {values = dense<19689> : tensor<1xi16> } : () -> tensor<1xi16>
+ %shift = "tosa.const"() {values = dense<15> : tensor<1xi8> } : () -> tensor<1xi8>
+ %input_zp = "tosa.const"() {values = dense<0> : tensor<1xi48>} : () -> tensor<1xi48>
+ %output_zp = "tosa.const"() {values = dense<-22> : tensor<1xi8>} : () -> tensor<1xi8>
+ %1 = tosa.rescale %arg0, %multiplier, %shift, %input_zp, %output_zp {scale32 = false, rounding_mode = "SINGLE_ROUND", per_channel = false, input_unsigned = false, output_unsigned = true} : (tensor<2xi48>, tensor<1xi16>, tensor<1xi8>, tensor<1xi48>, tensor<1xi8>) -> tensor<2xi8>
+
+ // CHECK: return
+ return
+}
+
// -----
// CHECK: #[[$MAP0:.*]] = affine_map<(d0) -> (d0)>
``````````
</details>
https://github.com/llvm/llvm-project/pull/138313
More information about the Mlir-commits
mailing list