From 78fa5112b4c2dcd94b78ee79baddebbf14d6ad98 Mon Sep 17 00:00:00 2001 From: Roger Sayle Date: Tue, 24 Aug 2021 02:59:02 +0100 Subject: [PATCH] [Committed] PR middle-end/102029: Stricter typing in LSHIFT_EXPR sign folding. My sincere apologies to everyone (again). As diagnosed by Jakub Jelinek, my recent patch to fold the signedness of LSHIFT_EXPR needs to be careful not to attempt transforming a left shift in an integer type into an invalid left shift of a pointer type. 2021-08-24 Roger Sayle Jakub Jelinek gcc/ChangeLog PR middle-end/102029 * match.pd (shift transformations): Add an additional check for !POINTER_TYPE_P in the recently added left shift transformation. gcc/testsuite/ChangeLog PR middle-end/102029 * gcc.dg/fold-convlshift-3.c: New test case. --- gcc/match.pd | 4 +++- gcc/testsuite/gcc.dg/fold-convlshift-3.c | 8 ++++++++ 2 files changed, 11 insertions(+), 1 deletion(-) create mode 100644 gcc/testsuite/gcc.dg/fold-convlshift-3.c diff --git a/gcc/match.pd b/gcc/match.pd index 978a1b0172ed..e5bbb123a6ad 100644 --- a/gcc/match.pd +++ b/gcc/match.pd @@ -3389,7 +3389,9 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT) the form that minimizes the number of conversions. */ (simplify (convert (lshift:s@0 (convert:s@1 @2) INTEGER_CST@3)) - (if (tree_nop_conversion_p (type, TREE_TYPE (@0)) + (if (INTEGRAL_TYPE_P (type) + && !POINTER_TYPE_P (type) + && tree_nop_conversion_p (type, TREE_TYPE (@0)) && INTEGRAL_TYPE_P (TREE_TYPE (@2)) && TYPE_PRECISION (TREE_TYPE (@2)) <= TYPE_PRECISION (type)) (lshift (convert @2) @3))) diff --git a/gcc/testsuite/gcc.dg/fold-convlshift-3.c b/gcc/testsuite/gcc.dg/fold-convlshift-3.c new file mode 100644 index 000000000000..8d01191f1971 --- /dev/null +++ b/gcc/testsuite/gcc.dg/fold-convlshift-3.c @@ -0,0 +1,8 @@ +/* PR middle-end/102029 */ +/* { dg-do compile } */ +/* { dg-options "-O2" } */ +int * +foo (const __PTRDIFF_TYPE__ l) +{ + return (int *) (l << 2); +} -- 2.47.3