[Mlir-commits] [mlir] [SCF] Make loop prefectching safe for overflow (PR #172066)

[llvmlistbot at llvm.org]

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@@ -283,7 +283,8 @@ LogicalResult LoopPipelinerInternal::emitPrologue(RewriterBase &rewriter) {
           arith::MulIOp::create(
               rewriter, loc, step,
               arith::ConstantOp::create(rewriter, loc,
-                                        rewriter.getIntegerAttr(t, i))));
+                                        rewriter.getIntegerAttr(t, i))),
+          arith::IntegerOverflowFlags::nsw);
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MaheshRavishankar wrote:

Yeah, exactly. I dont know how to phrase the question yet, but I think we can add this nsw trait if the original loop as some way of saying `lb + i * step` does not overflow. Still formalizing the whole thing so I am not ready to raise a broader question here yet.

https://github.com/llvm/llvm-project/pull/172066