From cf0c42c2ca04c3ae9fa20ce9dd4f6bce301bd37b Mon Sep 17 00:00:00 2001 From: fumiyanokesinn Date: Sun, 25 Jan 2026 23:59:25 +0900 Subject: cmd/compile/internal/reflectdata: fix divide by zero for zero-size array elements When generating equality signatures for arrays with zero-size ASPECIAL elements (e.g., [3]struct{_ [0]float64}), the compiler crashed with a divide by zero error when computing the loop unroll factor. Skip comparison code generation for zero-size elements since they need no comparison. Fixes #77303 Change-Id: Ib432cfece22b1cb714de4f0a0b0d1a2d89bb0d33 Reviewed-on: https://go-review.googlesource.com/c/go/+/738841 Reviewed-by: Cherry Mui Auto-Submit: Cuong Manh Le LUCI-TryBot-Result: Go LUCI Reviewed-by: Cuong Manh Le Reviewed-by: Keith Randall --- src/cmd/compile/internal/reflectdata/alg.go | 3 +++ 1 file changed, 3 insertions(+) (limited to 'src/cmd') diff --git a/src/cmd/compile/internal/reflectdata/alg.go b/src/cmd/compile/internal/reflectdata/alg.go index eb46ed84aa..f74a42eac1 100644 --- a/src/cmd/compile/internal/reflectdata/alg.go +++ b/src/cmd/compile/internal/reflectdata/alg.go @@ -785,6 +785,9 @@ func (e *eqSigBuilder) build(t *types.Type) { // The generated loops are kind of inefficient as well, // so unroll the loop a bit. const unrollSize = 32 // make loop body compare around this many bytes + if et.Size() == 0 { + break // zero-size elements need no comparison + } unroll := max(1, unrollSize/et.Size()) // Do partial loops directly. for n%unroll != 0 { -- cgit v1.3