| Message ID | 20180815125709.GA31341@arm.com |
|---|---|
| State | New |
| Headers | show |
| Series | [mid-end] Fix DSE big-endian subreg crash | expand |
On 08/15/2018 06:57 AM, Tamar Christina wrote: > Hi All, > > 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. > > I don't have a target independent test for this because it depends > on the target having a 48byte mode and using it for loads. > > Cross compiled and regtested on > aarch64_be-none-elf > and no issues > > Boostrapped and regtested > aarch64-none-linux-gnu > > and found no issues. > > Bootstrapped on > x86_64-pc-linux-gnu > arm-none-linux-gnueabihf > > and no issues. > > Ok for trunk? > > Thanks, > Tamar > > gcc/ChangeLog: > > 2018-08-15 Tamar Christina <tamar.christina@arm.com> > > * expmed.c (extract_low_bits): Reject invalid subregs early. > > gcc/testsuite/ChangeLog: > > 2018-08-15 Tamar Christina <tamar.christina@arm.com> > > * gcc.target/aarch64/large_struct_copy.c: New test. > OK. jeff
diff --git a/gcc/expmed.c b/gcc/expmed.c index 101e7b88107702b06276cfcd94319d6b79751368..8a1222fa69e88fa7ee6e2c3210d6747d6536de98 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/gcc.target/aarch64/large_struct_copy.c b/gcc/testsuite/gcc.target/aarch64/large_struct_copy.c new file mode 100644 index 0000000000000000000000000000000000000000..2b5e7801bad0598138cbcee7b2f4ffffaaf438df --- /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; +} +