From daa9715842345da5b9c440a9fef1ed3bc916bc18 Mon Sep 17 00:00:00 2001 From: Tamar Christina Date: Tue, 21 Aug 2018 09:55:07 +0000 Subject: [PATCH] Fix DSE big-endian subreg crash on AArch64. This patch fixes an ICE that would happen when extract_low_bits is called with modes for which you can't extract a valid subreg. e.g. taking a 32 bytes subreg from a 48 byte mode. The ICE happens because convert_modes which eventually calls simplify_gen_subreg does not expect the convertion to fail. The assert in gen_lowpart_general would then be hit. The patch changes it to validate the subreg before trying to convert the modes. If the subreg is not possible we return NULL_RTX and bail out early. gcc/ChangeLog: 2018-08-21 Tamar Christina * expmed.c (extract_low_bits): Reject invalid subregs early. gcc/testsuite/ChangeLog: 2018-08-21 Tamar Christina * gcc.target/aarch64/large_struct_copy.c: New test. From-SVN: r263696 --- gcc/ChangeLog | 4 ++++ gcc/expmed.c | 4 ++++ gcc/testsuite/ChangeLog | 4 ++++ .../gcc.target/aarch64/large_struct_copy.c | 23 +++++++++++++++++++ 4 files changed, 35 insertions(+) create mode 100644 gcc/testsuite/gcc.target/aarch64/large_struct_copy.c diff --git a/gcc/ChangeLog b/gcc/ChangeLog index b4b7fe0b27e..66ca10b96b9 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,7 @@ +2018-08-21 Tamar Christina + + * expmed.c (extract_low_bits): Reject invalid subregs early. + 2018-08-21 Bernd Edlinger PR middle-end/86121 diff --git a/gcc/expmed.c b/gcc/expmed.c index be9f0ec9011..e2819309e4b 100644 --- a/gcc/expmed.c +++ b/gcc/expmed.c @@ -2392,6 +2392,10 @@ extract_low_bits (machine_mode mode, machine_mode src_mode, rtx src) return NULL_RTX; src = gen_lowpart (src_int_mode, src); + if (!validate_subreg (int_mode, src_int_mode, src, + subreg_lowpart_offset (int_mode, src_int_mode))) + return NULL_RTX; + src = convert_modes (int_mode, src_int_mode, src, true); src = gen_lowpart (mode, src); return src; diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog index ccdaa1e32a1..42117a60523 100644 --- a/gcc/testsuite/ChangeLog +++ b/gcc/testsuite/ChangeLog @@ -1,3 +1,7 @@ +2018-08-21 Tamar Christina + + * gcc.target/aarch64/large_struct_copy.c: New test. + 2018-08-21 Szabolcs Nagy * g++.dg/torture/pr86763.C: Restrict to *-*-linux*. diff --git a/gcc/testsuite/gcc.target/aarch64/large_struct_copy.c b/gcc/testsuite/gcc.target/aarch64/large_struct_copy.c new file mode 100644 index 00000000000..2b5e7801bad --- /dev/null +++ b/gcc/testsuite/gcc.target/aarch64/large_struct_copy.c @@ -0,0 +1,23 @@ +/* { dg-do compile } */ +/* { dg-options "-O2" } */ + +typedef unsigned __attribute__((mode(DI))) uint64_t; + +struct S0 { + uint64_t f1; + uint64_t f2; + uint64_t f3; + uint64_t f4; + uint64_t f5; +} a; +struct S2 { + uint64_t f0; + uint64_t f2; + struct S0 f3; +}; + +void fn1 () { + struct S2 b = {0, 1, 7, 4073709551611, 4, 8, 7}; + a = b.f3; +} + -- 2.30.2