From 5561b41dd67630273479d7661638c5c36a5abb5b Mon Sep 17 00:00:00 2001 From: Ian Lance Taylor Date: Tue, 7 Jan 2020 15:35:04 +0000 Subject: [PATCH] compiler: avoid write barrier for a[i] = a[i][:v] This avoids generating a write barrier for code that appears in the Go1.14beta1 runtime package in (*pageAlloc).sysGrow: s.summary[l] = s.summary[l][:needIdxLimit] Reviewed-on: https://go-review.googlesource.com/c/gofrontend/+/213558 From-SVN: r279962 --- gcc/go/gofrontend/MERGE | 2 +- gcc/go/gofrontend/expressions.cc | 18 ++++++++++++++++++ 2 files changed, 19 insertions(+), 1 deletion(-) diff --git a/gcc/go/gofrontend/MERGE b/gcc/go/gofrontend/MERGE index 6dca40fe31a..9f825daa5fe 100644 --- a/gcc/go/gofrontend/MERGE +++ b/gcc/go/gofrontend/MERGE @@ -1,4 +1,4 @@ -d0a102eea2262e3fca89b1eb342fd03328c4aa16 +86d223eaccecff72b44cd23a014bc028b658055e The first line of this file holds the git revision number of the last merge done from the gofrontend repository. diff --git a/gcc/go/gofrontend/expressions.cc b/gcc/go/gofrontend/expressions.cc index 8d72b1f478c..c228905eb5e 100644 --- a/gcc/go/gofrontend/expressions.cc +++ b/gcc/go/gofrontend/expressions.cc @@ -183,6 +183,24 @@ Expression::is_same_variable(Expression* a, Expression* b) bu->operand())); } + Array_index_expression* aie = a->array_index_expression(); + if (aie != NULL) + { + Array_index_expression* bie = b->array_index_expression(); + return (aie->end() == NULL + && bie->end() == NULL + && Expression::is_same_variable(aie->array(), bie->array()) + && Expression::is_same_variable(aie->start(), bie->start())); + } + + Numeric_constant aval; + if (a->numeric_constant_value(&aval)) + { + Numeric_constant bval; + if (b->numeric_constant_value(&bval)) + return aval.equals(bval); + } + return false; } -- 2.30.2