[Bug middle-end/101062] [10 Regression] wrong code with "-O2 -fno-toplevel-reorder -frename-registers"
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101062 Jakub Jelinek changed: What|Removed |Added Status|ASSIGNED|RESOLVED Resolution|--- |FIXED --- Comment #24 from Jakub Jelinek --- Fixed.
[Bug middle-end/101062] [10 Regression] wrong code with "-O2 -fno-toplevel-reorder -frename-registers"
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101062 --- Comment #23 from CVS Commits --- The releases/gcc-9 branch has been updated by Jakub Jelinek : https://gcc.gnu.org/g:80f194b25f573b409ada5761778fb6dfb3cf85e9 commit r9-10080-g80f194b25f573b409ada5761778fb6dfb3cf85e9 Author: Jakub Jelinek Date: Fri Jun 18 11:20:40 2021 +0200 stor-layout: Don't create DECL_BIT_FIELD_REPRESENTATIVE for QUAL_UNION_TYPE [PR101062] > The following patch does create them, but treats all such bitfields as if > they were in a structure where the particular bitfield is the only field. While the patch passed bootstrap/regtest on the trunk, when trying to backport it to 11 branch the bootstrap failed with atree.ads:3844:34: size for "Node_Record" too small errors. Turns out the error is not about size being too small, but actually about size being non-constant, and comes from: /* In a FIELD_DECL of a RECORD_TYPE, this is a pointer to the storage representative FIELD_DECL. */ #define DECL_BIT_FIELD_REPRESENTATIVE(NODE) \ (FIELD_DECL_CHECK (NODE)->field_decl.qualifier) /* For a FIELD_DECL in a QUAL_UNION_TYPE, records the expression, which if nonzero, indicates that the field occupies the type. */ #define DECL_QUALIFIER(NODE) (FIELD_DECL_CHECK (NODE)->field_decl.qualifier) so by setting up DECL_BIT_FIELD_REPRESENTATIVE in QUAL_UNION_TYPE we actually set or modify DECL_QUALIFIER and then construct size as COND_EXPRs with those bit field representatives (e.g. with array type) as conditions which doesn't fold into constant. The following patch fixes it by not creating DECL_BIT_FIELD_REPRESENTATIVEs for QUAL_UNION_TYPE as there is nowhere to store them, Shall we change tree.h to document that DECL_BIT_FIELD_REPRESENTATIVE is valid also on UNION_TYPE? I see: tree-ssa-alias.c- if (TREE_CODE (type1) == RECORD_TYPE tree-ssa-alias.c: && DECL_BIT_FIELD_REPRESENTATIVE (field1)) tree-ssa-alias.c:field1 = DECL_BIT_FIELD_REPRESENTATIVE (field1); tree-ssa-alias.c- if (TREE_CODE (type2) == RECORD_TYPE tree-ssa-alias.c: && DECL_BIT_FIELD_REPRESENTATIVE (field2)) tree-ssa-alias.c:field2 = DECL_BIT_FIELD_REPRESENTATIVE (field2); Shall we change that to || == UNION_TYPE or do we assume all fields are overlapping in a UNION_TYPE already? At other spots (asan, ubsan, expr.c) it is unclear what will happen if they see a QUAL_UNION_TYPE with a DECL_QUALIFIER (or does the Ada FE lower that somehow)? 2021-06-18 Jakub Jelinek PR middle-end/101062 * stor-layout.c (finish_bitfield_layout): Don't add bitfield representatives in QUAL_UNION_TYPE. (cherry picked from commit 3587c2c241eda0f3ab54ea60d46e9caf12d69b5a)
[Bug middle-end/101062] [10 Regression] wrong code with "-O2 -fno-toplevel-reorder -frename-registers"
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101062 --- Comment #22 from CVS Commits --- The releases/gcc-9 branch has been updated by Jakub Jelinek : https://gcc.gnu.org/g:d0b1d8d3b85bb4466fae20e72a8fa35dd7277229 commit r9-10079-gd0b1d8d3b85bb4466fae20e72a8fa35dd7277229 Author: Jakub Jelinek Date: Wed Jun 16 12:17:55 2021 +0200 stor-layout: Create DECL_BIT_FIELD_REPRESENTATIVE even for bitfields in unions [PR101062] The following testcase is miscompiled on x86_64-linux, the bitfield store is implemented as a RMW 64-bit operation at d+24 when the d variable has size of only 28 bytes and scheduling moves in between the R and W part a store to a different variable that happens to be right after the d variable. The reason for this is that we weren't creating DECL_BIT_FIELD_REPRESENTATIVEs for bitfields in unions. The following patch does create them, but treats all such bitfields as if they were in a structure where the particular bitfield is the only field. 2021-06-16 Jakub Jelinek PR middle-end/101062 * stor-layout.c (finish_bitfield_representative): For fields in unions assume nextf is always NULL. (finish_bitfield_layout): Compute bit field representatives also in unions, but handle it as if each bitfield was the only field in the aggregate. * gcc.dg/pr101062.c: New test. (cherry picked from commit b4b50bf2864e09f028a39a3f460222632c4d7348)
[Bug middle-end/101062] [10 Regression] wrong code with "-O2 -fno-toplevel-reorder -frename-registers"
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101062 --- Comment #21 from CVS Commits --- The releases/gcc-10 branch has been updated by Jakub Jelinek : https://gcc.gnu.org/g:3df2f5828752a91343d01defb215de326b5ddb4c commit r10-10623-g3df2f5828752a91343d01defb215de326b5ddb4c Author: Jakub Jelinek Date: Fri Jun 18 11:20:40 2021 +0200 stor-layout: Don't create DECL_BIT_FIELD_REPRESENTATIVE for QUAL_UNION_TYPE [PR101062] > The following patch does create them, but treats all such bitfields as if > they were in a structure where the particular bitfield is the only field. While the patch passed bootstrap/regtest on the trunk, when trying to backport it to 11 branch the bootstrap failed with atree.ads:3844:34: size for "Node_Record" too small errors. Turns out the error is not about size being too small, but actually about size being non-constant, and comes from: /* In a FIELD_DECL of a RECORD_TYPE, this is a pointer to the storage representative FIELD_DECL. */ #define DECL_BIT_FIELD_REPRESENTATIVE(NODE) \ (FIELD_DECL_CHECK (NODE)->field_decl.qualifier) /* For a FIELD_DECL in a QUAL_UNION_TYPE, records the expression, which if nonzero, indicates that the field occupies the type. */ #define DECL_QUALIFIER(NODE) (FIELD_DECL_CHECK (NODE)->field_decl.qualifier) so by setting up DECL_BIT_FIELD_REPRESENTATIVE in QUAL_UNION_TYPE we actually set or modify DECL_QUALIFIER and then construct size as COND_EXPRs with those bit field representatives (e.g. with array type) as conditions which doesn't fold into constant. The following patch fixes it by not creating DECL_BIT_FIELD_REPRESENTATIVEs for QUAL_UNION_TYPE as there is nowhere to store them, Shall we change tree.h to document that DECL_BIT_FIELD_REPRESENTATIVE is valid also on UNION_TYPE? I see: tree-ssa-alias.c- if (TREE_CODE (type1) == RECORD_TYPE tree-ssa-alias.c: && DECL_BIT_FIELD_REPRESENTATIVE (field1)) tree-ssa-alias.c:field1 = DECL_BIT_FIELD_REPRESENTATIVE (field1); tree-ssa-alias.c- if (TREE_CODE (type2) == RECORD_TYPE tree-ssa-alias.c: && DECL_BIT_FIELD_REPRESENTATIVE (field2)) tree-ssa-alias.c:field2 = DECL_BIT_FIELD_REPRESENTATIVE (field2); Shall we change that to || == UNION_TYPE or do we assume all fields are overlapping in a UNION_TYPE already? At other spots (asan, ubsan, expr.c) it is unclear what will happen if they see a QUAL_UNION_TYPE with a DECL_QUALIFIER (or does the Ada FE lower that somehow)? 2021-06-18 Jakub Jelinek PR middle-end/101062 * stor-layout.c (finish_bitfield_layout): Don't add bitfield representatives in QUAL_UNION_TYPE. (cherry picked from commit 3587c2c241eda0f3ab54ea60d46e9caf12d69b5a)
[Bug middle-end/101062] [10 Regression] wrong code with "-O2 -fno-toplevel-reorder -frename-registers"
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101062 --- Comment #20 from CVS Commits --- The releases/gcc-10 branch has been updated by Jakub Jelinek : https://gcc.gnu.org/g:0a278a8e2a95abe2bdad50ffd820b31363758a78 commit r10-10622-g0a278a8e2a95abe2bdad50ffd820b31363758a78 Author: Jakub Jelinek Date: Wed Jun 16 12:17:55 2021 +0200 stor-layout: Create DECL_BIT_FIELD_REPRESENTATIVE even for bitfields in unions [PR101062] The following testcase is miscompiled on x86_64-linux, the bitfield store is implemented as a RMW 64-bit operation at d+24 when the d variable has size of only 28 bytes and scheduling moves in between the R and W part a store to a different variable that happens to be right after the d variable. The reason for this is that we weren't creating DECL_BIT_FIELD_REPRESENTATIVEs for bitfields in unions. The following patch does create them, but treats all such bitfields as if they were in a structure where the particular bitfield is the only field. 2021-06-16 Jakub Jelinek PR middle-end/101062 * stor-layout.c (finish_bitfield_representative): For fields in unions assume nextf is always NULL. (finish_bitfield_layout): Compute bit field representatives also in unions, but handle it as if each bitfield was the only field in the aggregate. * gcc.dg/pr101062.c: New test. (cherry picked from commit b4b50bf2864e09f028a39a3f460222632c4d7348)
[Bug middle-end/101062] [10 Regression] wrong code with "-O2 -fno-toplevel-reorder -frename-registers"
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101062 Jakub Jelinek changed: What|Removed |Added Summary|[10/11/12 Regression] wrong |[10 Regression] wrong code |code with "-O2 |with "-O2 |-fno-toplevel-reorder |-fno-toplevel-reorder |-frename-registers" |-frename-registers" --- Comment #19 from Jakub Jelinek --- Fixed for 11.2 and trunk so far.
