diff options
Diffstat (limited to 'toolchain/gcc/patches/11.2.0/001-v11.3.0-ranger-Fix-up-fold_using_range-range_of_address-PR10.patch')
-rw-r--r-- | toolchain/gcc/patches/11.2.0/001-v11.3.0-ranger-Fix-up-fold_using_range-range_of_address-PR10.patch | 114 |
1 files changed, 114 insertions, 0 deletions
diff --git a/toolchain/gcc/patches/11.2.0/001-v11.3.0-ranger-Fix-up-fold_using_range-range_of_address-PR10.patch b/toolchain/gcc/patches/11.2.0/001-v11.3.0-ranger-Fix-up-fold_using_range-range_of_address-PR10.patch new file mode 100644 index 0000000000..71bbfe5a1d --- /dev/null +++ b/toolchain/gcc/patches/11.2.0/001-v11.3.0-ranger-Fix-up-fold_using_range-range_of_address-PR10.patch @@ -0,0 +1,114 @@ +From a6219e8e0719b14f474b0dcaa7bde2f4e57474f9 Mon Sep 17 00:00:00 2001 +From: Jakub Jelinek <jakub@redhat.com> +Date: Wed, 17 Nov 2021 13:45:53 +0100 +Subject: [PATCH] ranger: Fix up fold_using_range::range_of_address [PR103255] + +If on &base->member the offset isn't constant or isn't zero and +-fdelete-null-pointer-checks and not -fwrapv-pointer and base has a range +that doesn't include NULL, we return the range of the base. +Usually it isn't a big deal, because for most pointers we just use +varying, range_zero and range_nonzero ranges and nothing beyond that, +but if a pointer is initialized from a constant, we actually track the +exact range and in that case this causes miscompilation. +As discussed on IRC, I think doing something like: + offset_int off2; + if (off_cst && off.is_constant (&off2)) + { + tree cst = wide_int_to_tree (sizetype, off2 / BITS_PER_UNIT); + // adjust range r with POINTER_PLUS_EXPR cst + if (!range_includes_zero_p (&r)) + return true; + } + // Fallback + r = range_nonzero (TREE_TYPE (gimple_assign_rhs1 (stmt))); + return true; +could work, given that most of the pointer ranges are just the simple ones +perhaps it is too much for little benefit. + +2021-11-17 Jakub Jelinek <jakub@redhat.com> + + PR tree-optimization/103255 + * gimple-range.cc (fold_using_range::range_of_address): Return + range_nonzero rather than unadjusted base's range. Formatting fixes. + + * gcc.c-torture/execute/pr103255.c: New test. + +(cherry picked from commit c39cb6bf835ca12e590eaa6f90222e51be207c50) +--- + gcc/gimple-range.cc | 16 +++++--- + .../gcc.c-torture/execute/pr103255.c | 41 +++++++++++++++++++ + 2 files changed, 52 insertions(+), 5 deletions(-) + create mode 100644 gcc/testsuite/gcc.c-torture/execute/pr103255.c + +--- a/gcc/gimple-range.cc ++++ b/gcc/gimple-range.cc +@@ -491,14 +491,20 @@ gimple_ranger::range_of_address (irange + } + /* If &X->a is equal to X, the range of X is the result. */ + if (off_cst && known_eq (off, 0)) +- return true; ++ return true; + else if (flag_delete_null_pointer_checks + && !TYPE_OVERFLOW_WRAPS (TREE_TYPE (expr))) + { +- /* For -fdelete-null-pointer-checks -fno-wrapv-pointer we don't +- allow going from non-NULL pointer to NULL. */ +- if(!range_includes_zero_p (&r)) +- return true; ++ /* For -fdelete-null-pointer-checks -fno-wrapv-pointer we don't ++ allow going from non-NULL pointer to NULL. */ ++ if (!range_includes_zero_p (&r)) ++ { ++ /* We could here instead adjust r by off >> LOG2_BITS_PER_UNIT ++ using POINTER_PLUS_EXPR if off_cst and just fall back to ++ this. */ ++ r = range_nonzero (TREE_TYPE (gimple_assign_rhs1 (stmt))); ++ return true; ++ } + } + /* If MEM_REF has a "positive" offset, consider it non-NULL + always, for -fdelete-null-pointer-checks also "negative" +--- /dev/null ++++ b/gcc/testsuite/gcc.c-torture/execute/pr103255.c +@@ -0,0 +1,41 @@ ++/* PR tree-optimization/103255 */ ++ ++struct H ++{ ++ unsigned a; ++ unsigned b; ++ unsigned c; ++}; ++ ++#if __SIZEOF_POINTER__ >= 4 ++#define ADDR 0x400000 ++#else ++#define ADDR 0x4000 ++#endif ++#define OFF 0x20 ++ ++int ++main () ++{ ++ struct H *h = 0; ++ unsigned long o; ++ volatile int t = 1; ++ ++ for (o = OFF; o <= OFF; o += 0x1000) ++ { ++ struct H *u; ++ u = (struct H *) (ADDR + o); ++ if (t) ++ { ++ h = u; ++ break; ++ } ++ } ++ ++ if (h == 0) ++ return 0; ++ unsigned *tt = &h->b; ++ if ((__SIZE_TYPE__) tt != (ADDR + OFF + __builtin_offsetof (struct H, b))) ++ __builtin_abort (); ++ return 0; ++} |