[Mlir-commits] [mlir] Introduce `arith.scaling_extf` and `arith.scaling_truncf` (PR #141965)
Daniel Hernandez-Juarez
llvmlistbot at llvm.org
Fri May 30 02:53:27 PDT 2025
================
@@ -409,6 +421,125 @@ struct F8E8M0TruncFOpConverter : public OpRewritePattern<arith::TruncFOp> {
}
};
+struct ScalingExtFOpConverter : public OpRewritePattern<arith::ScalingExtFOp> {
+ using OpRewritePattern::OpRewritePattern;
+ LogicalResult matchAndRewrite(arith::ScalingExtFOp op,
+ PatternRewriter &rewriter) const final {
+ ImplicitLocOpBuilder b(op.getLoc(), rewriter);
+ Value inputOperand = op.getIn();
+ Value scaleOperand = op.getScale();
+ Type scaleETy = getElementTypeOrSelf(scaleOperand);
+ // allow implicit exponent extraction from 16/32 bits floats
+ if (scaleETy.getIntOrFloatBitWidth() >= 16) {
+ scaleETy = b.getF8E8M0Type();
+ scaleOperand = b.create<arith::TruncFOp>(scaleETy, scaleOperand);
+ }
+ if (!llvm::isa<Float8E8M0FNUType>(scaleETy)) {
+ return rewriter.notifyMatchFailure(
+ op, "scaling extf is not using scale operand of type f8E8M0FNU");
+ }
+ Type resultTy = op.getType();
+ // extf on scale will essentially create f32 number that is 2^scale and will
+ // also propagate NaNs
+ Value scaleExt = b.create<arith::ExtFOp>(resultTy, scaleOperand);
+ Value inputExt = b.create<arith::ExtFOp>(resultTy, inputOperand);
+ Value result = b.create<arith::MulFOp>(inputExt, scaleExt);
+ rewriter.replaceOp(op, result);
+ return success();
+ }
+};
+
+struct ScalingTruncFOpConverter
+ : public OpRewritePattern<arith::ScalingTruncFOp> {
+ using OpRewritePattern::OpRewritePattern;
+ LogicalResult matchAndRewrite(arith::ScalingTruncFOp op,
+ PatternRewriter &rewriter) const final {
+ ImplicitLocOpBuilder b(op.getLoc(), rewriter);
+ Value inputOperand = op.getIn();
+ Value scaleOperand = op.getScale();
+ Type scaleTy = scaleOperand.getType();
+ Type scaleETy = getElementTypeOrSelf(scaleOperand);
+ // allow implicit exponent extraction from 16/32 bits floats
+ if (scaleETy.getIntOrFloatBitWidth() >= 16) {
+ scaleETy = b.getF8E8M0Type();
+ scaleOperand = b.create<arith::TruncFOp>(scaleETy, scaleOperand);
+ scaleTy = scaleOperand.getType();
+ }
+ if (!llvm::isa<Float8E8M0FNUType>(scaleETy)) {
+ return rewriter.notifyMatchFailure(
+ op, "scaling truncf is not using scale operand of type f8E8M0FNU");
----------------
dhernandez0 wrote:
I guess this can happen if scaleETy is f4, f6 or other f8 types. So, truncf wouldn't run, right? The error message is confusing IMO.
https://github.com/llvm/llvm-project/pull/141965
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