From: Andrew Pinski Date: Fri, 2 Jun 2023 04:17:56 +0000 (-0700) Subject: rtl-optimization: [PR102733] DSE removing address which only differ by address space. X-Git-Tag: basepoints/gcc-15~8631 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=64ca6aa74b6b5a9737f3808bf4a947dd5c122d47;p=thirdparty%2Fgcc.git rtl-optimization: [PR102733] DSE removing address which only differ by address space. The problem here is DSE was not taking into account the address space which meant if you had two addresses say `fs:0` and `gs:0` (on x86_64), DSE would think they were the same and remove the first store. This fixes that issue by adding a check for the address space too. OK? Bootstrapped and tested on x86_64-linux-gnu with no regressions. PR rtl-optimization/102733 gcc/ChangeLog: * dse.cc (store_info): Add addrspace field. (record_store): Record the address space and check to make sure they are the same. gcc/testsuite/ChangeLog: * gcc.target/i386/addr-space-6.c: New test. --- diff --git a/gcc/dse.cc b/gcc/dse.cc index 802b949cfb25..8b07be17674c 100644 --- a/gcc/dse.cc +++ b/gcc/dse.cc @@ -251,6 +251,9 @@ public: and known (rather than -1). */ poly_int64 width; + /* The address space that the memory reference uses. */ + unsigned char addrspace; + union { /* A bitmask as wide as the number of bytes in the word that @@ -1524,6 +1527,7 @@ record_store (rtx body, bb_info_t bb_info) ptr = active_local_stores; last = NULL; redundant_reason = NULL; + unsigned char addrspace = MEM_ADDR_SPACE (mem); mem = canon_rtx (mem); if (group_id < 0) @@ -1548,7 +1552,9 @@ record_store (rtx body, bb_info_t bb_info) while (!s_info->is_set) s_info = s_info->next; - if (s_info->group_id == group_id && s_info->cse_base == base) + if (s_info->group_id == group_id + && s_info->cse_base == base + && s_info->addrspace == addrspace) { HOST_WIDE_INT i; if (dump_file && (dump_flags & TDF_DETAILS)) @@ -1688,6 +1694,7 @@ record_store (rtx body, bb_info_t bb_info) store_info->rhs = rhs; store_info->const_rhs = const_rhs; store_info->redundant_reason = redundant_reason; + store_info->addrspace = addrspace; /* If this is a clobber, we return 0. We will only be able to delete this insn if there is only one store USED store, but we diff --git a/gcc/testsuite/gcc.target/i386/addr-space-6.c b/gcc/testsuite/gcc.target/i386/addr-space-6.c new file mode 100644 index 000000000000..82eca4d7e0c3 --- /dev/null +++ b/gcc/testsuite/gcc.target/i386/addr-space-6.c @@ -0,0 +1,21 @@ +/* PR rtl-optimization/102733 */ +/* { dg-do compile } */ +/* { dg-options "-O1" } */ + +/* DSE was removing a store to fs:0 (correctly) + and gs:0 (incorrectly) as DSE didn't take into + account the address space was different. */ + +void test_null_store (void) +{ + int __seg_fs *fs = (int __seg_fs *)0; + *fs = 1; + + int __seg_gs *gs = (int __seg_gs *)0; + *gs = 2; + *fs = 3; +} + +/* { dg-final { scan-assembler-times "movl\t" 2 } } */ +/* { dg-final { scan-assembler "gs:" } } */ +/* { dg-final { scan-assembler "fs:" } } */