Message ID | 20130814130922.GO1814@tucnak.redhat.com |
---|---|
State | New |
Headers | show |
Jakub Jelinek <jakub@redhat.com> wrote: >Hi! > >On the following testcases we miscompile the code (on -1.c just drop >= {v} from the statements, on -2.c lim moves the volatile stores after >the >loop), because SRA drops the volatileness from the MEM_REF. > >SRA generally ignores volatile vars and fields etc., but if we have a >structure assignment to volatile from non-volatile or vice versa, >if SRA decides to scalarize rhs resp. lhs, new MEM_REFs are created >even >for the volatile access with different type. > >The following patch fixes that by propagating TREE_THIS_VOLATILE and >TREE_SIDE_EFFECTS from the prev_base to the newly created MEM_REF. > >Bootstrapped/regtested on x86_64-linux and i686-linux, ok for >trunk/4.8? You do not need the volatile qualified type, and IIRC we're not consistent in setting tree-sideeffects either. Thus, Ok with not doing the volatile qualification. Thanks, Richard. >On IRC with Martin we've also discussed slsr in this regard, but that >seems >to be fine, it uses the original volatile type if it was volatile and >propagates TREE_THIS_VOLATILE/TREE_SIDE_EFFECTS flags to the newly >created >MEM_REF. > >2013-08-14 Jakub Jelinek <jakub@redhat.com> > > PR tree-optimization/58145 > * tree-sra.c (build_ref_for_offset): If base is TREE_THIS_VOLATILE, > propagate it to exp_type and MEM_REF. > > * gcc.dg/pr58145-1.c: New test. > * gcc.dg/pr58145-2.c: New test. > >--- gcc/tree-sra.c.jj 2013-08-14 11:02:55.290711106 +0200 >+++ gcc/tree-sra.c 2013-08-14 12:38:47.405230042 +0200 >@@ -1466,6 +1466,7 @@ build_ref_for_offset (location_t loc, tr > { > tree prev_base = base; > tree off; >+ tree mem_ref; > HOST_WIDE_INT base_offset; > unsigned HOST_WIDE_INT misalign; > unsigned int align; >@@ -1515,8 +1516,17 @@ build_ref_for_offset (location_t loc, tr > align = (misalign & -misalign); > if (align < TYPE_ALIGN (exp_type)) > exp_type = build_aligned_type (exp_type, align); >- >- return fold_build2_loc (loc, MEM_REF, exp_type, base, off); >+ if (TREE_THIS_VOLATILE (TREE_TYPE (prev_base)) >+ && !TREE_THIS_VOLATILE (exp_type)) >+ exp_type = build_qualified_type (exp_type, TYPE_QUALS (exp_type) >+ | TYPE_QUAL_VOLATILE); >+ >+ mem_ref = fold_build2_loc (loc, MEM_REF, exp_type, base, off); >+ if (TREE_THIS_VOLATILE (exp_type) || TREE_THIS_VOLATILE (prev_base)) >+ TREE_THIS_VOLATILE (mem_ref) = 1; >+ if (TREE_SIDE_EFFECTS (prev_base)) >+ TREE_SIDE_EFFECTS (mem_ref) = 1; >+ return mem_ref; > } > >/* Construct a memory reference to a part of an aggregate BASE at the >given >--- gcc/testsuite/gcc.dg/pr58145-1.c.jj 2013-08-14 12:02:07.077086488 >+0200 >+++ gcc/testsuite/gcc.dg/pr58145-1.c 2013-08-14 12:03:15.895198976 >+0200 >@@ -0,0 +1,37 @@ >+/* PR tree-optimization/58145 */ >+/* { dg-do compile { target { int32plus } } } */ >+/* { dg-options "-O2 -fdump-tree-optimized" } */ >+ >+struct S { unsigned int data : 32; }; >+struct T { unsigned int data; }; >+volatile struct S s2; >+ >+void >+f1 (int val) >+{ >+ struct S s = { .data = val }; >+ *(volatile struct S *) 0x880000UL = s; >+} >+ >+void >+f2 (int val) >+{ >+ struct T t = { .data = val }; >+ *(volatile struct T *) 0x880000UL = t; >+} >+ >+void >+f3 (int val) >+{ >+ *(volatile unsigned int *) 0x880000UL = val; >+} >+ >+void >+f4 (int val) >+{ >+ struct S s = { .data = val }; >+ s2 = s; >+} >+ >+/* { dg-final { scan-tree-dump-times " ={v} " 4 "optimized" } } */ >+/* { dg-final { cleanup-tree-dump "optimized" } } */ >--- gcc/testsuite/gcc.dg/pr58145-2.c.jj 2013-08-14 12:02:28.409663559 >+0200 >+++ gcc/testsuite/gcc.dg/pr58145-2.c 2013-08-14 12:04:19.471612107 >+0200 >@@ -0,0 +1,51 @@ >+/* PR tree-optimization/58145 */ >+/* { dg-do compile { target { int32plus } } } */ >+/* { dg-options "-O2 -fdump-tree-optimized" } */ >+ >+struct S { unsigned int data : 32; }; >+struct T { unsigned int data; }; >+volatile struct S s2; >+ >+static inline void >+f1 (int val) >+{ >+ struct S s = { .data = val }; >+ *(volatile struct S *) 0x880000UL = s; >+} >+ >+static inline void >+f2 (int val) >+{ >+ struct T t = { .data = val }; >+ *(volatile struct T *) 0x880000UL = t; >+} >+ >+static inline void >+f3 (int val) >+{ >+ *(volatile unsigned int *) 0x880000UL = val; >+} >+ >+static inline void >+f4 (int val) >+{ >+ struct S s = { .data = val }; >+ s2 = s; >+} >+ >+void >+f5 (void) >+{ >+ int i; >+ for (i = 0; i < 100; i++) >+ f1 (0); >+ for (i = 0; i < 100; i++) >+ f2 (0); >+ for (i = 0; i < 100; i++) >+ f3 (0); >+ for (i = 0; i < 100; i++) >+ f4 (0); >+} >+ >+/* { dg-final { scan-tree-dump-times " ={v} " 4 "optimized" } } */ >+/* { dg-final { cleanup-tree-dump "optimized" } } */ > > Jakub
--- gcc/tree-sra.c.jj 2013-08-14 11:02:55.290711106 +0200 +++ gcc/tree-sra.c 2013-08-14 12:38:47.405230042 +0200 @@ -1466,6 +1466,7 @@ build_ref_for_offset (location_t loc, tr { tree prev_base = base; tree off; + tree mem_ref; HOST_WIDE_INT base_offset; unsigned HOST_WIDE_INT misalign; unsigned int align; @@ -1515,8 +1516,17 @@ build_ref_for_offset (location_t loc, tr align = (misalign & -misalign); if (align < TYPE_ALIGN (exp_type)) exp_type = build_aligned_type (exp_type, align); - - return fold_build2_loc (loc, MEM_REF, exp_type, base, off); + if (TREE_THIS_VOLATILE (TREE_TYPE (prev_base)) + && !TREE_THIS_VOLATILE (exp_type)) + exp_type = build_qualified_type (exp_type, TYPE_QUALS (exp_type) + | TYPE_QUAL_VOLATILE); + + mem_ref = fold_build2_loc (loc, MEM_REF, exp_type, base, off); + if (TREE_THIS_VOLATILE (exp_type) || TREE_THIS_VOLATILE (prev_base)) + TREE_THIS_VOLATILE (mem_ref) = 1; + if (TREE_SIDE_EFFECTS (prev_base)) + TREE_SIDE_EFFECTS (mem_ref) = 1; + return mem_ref; } /* Construct a memory reference to a part of an aggregate BASE at the given --- gcc/testsuite/gcc.dg/pr58145-1.c.jj 2013-08-14 12:02:07.077086488 +0200 +++ gcc/testsuite/gcc.dg/pr58145-1.c 2013-08-14 12:03:15.895198976 +0200 @@ -0,0 +1,37 @@ +/* PR tree-optimization/58145 */ +/* { dg-do compile { target { int32plus } } } */ +/* { dg-options "-O2 -fdump-tree-optimized" } */ + +struct S { unsigned int data : 32; }; +struct T { unsigned int data; }; +volatile struct S s2; + +void +f1 (int val) +{ + struct S s = { .data = val }; + *(volatile struct S *) 0x880000UL = s; +} + +void +f2 (int val) +{ + struct T t = { .data = val }; + *(volatile struct T *) 0x880000UL = t; +} + +void +f3 (int val) +{ + *(volatile unsigned int *) 0x880000UL = val; +} + +void +f4 (int val) +{ + struct S s = { .data = val }; + s2 = s; +} + +/* { dg-final { scan-tree-dump-times " ={v} " 4 "optimized" } } */ +/* { dg-final { cleanup-tree-dump "optimized" } } */ --- gcc/testsuite/gcc.dg/pr58145-2.c.jj 2013-08-14 12:02:28.409663559 +0200 +++ gcc/testsuite/gcc.dg/pr58145-2.c 2013-08-14 12:04:19.471612107 +0200 @@ -0,0 +1,51 @@ +/* PR tree-optimization/58145 */ +/* { dg-do compile { target { int32plus } } } */ +/* { dg-options "-O2 -fdump-tree-optimized" } */ + +struct S { unsigned int data : 32; }; +struct T { unsigned int data; }; +volatile struct S s2; + +static inline void +f1 (int val) +{ + struct S s = { .data = val }; + *(volatile struct S *) 0x880000UL = s; +} + +static inline void +f2 (int val) +{ + struct T t = { .data = val }; + *(volatile struct T *) 0x880000UL = t; +} + +static inline void +f3 (int val) +{ + *(volatile unsigned int *) 0x880000UL = val; +} + +static inline void +f4 (int val) +{ + struct S s = { .data = val }; + s2 = s; +} + +void +f5 (void) +{ + int i; + for (i = 0; i < 100; i++) + f1 (0); + for (i = 0; i < 100; i++) + f2 (0); + for (i = 0; i < 100; i++) + f3 (0); + for (i = 0; i < 100; i++) + f4 (0); +} + +/* { dg-final { scan-tree-dump-times " ={v} " 4 "optimized" } } */ +/* { dg-final { cleanup-tree-dump "optimized" } } */