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| author | Richard Biener <rguenther@suse.de> | 2022-12-11 14:07:34 +0100 |
|---|---|---|
| committer | Richard Biener <rguenther@suse.de> | 2022-12-11 14:45:30 +0100 |
| commit | d13b86f932ff7b9d8f41483fd869c637b67d4dec (patch) | |
| tree | d7ea798473c10c4812bd69a4331b03bf4c3dc7a4 /gcc | |
| parent | 26295a069fd312a8be4a6cd96643117383145cc0 (diff) | |
| download | gcc-d13b86f932ff7b9d8f41483fd869c637b67d4dec.zip gcc-d13b86f932ff7b9d8f41483fd869c637b67d4dec.tar.gz gcc-d13b86f932ff7b9d8f41483fd869c637b67d4dec.tar.bz2 | |
tree-optimization/89317 - missed folding of (p + 4) - &p->d
The PR notices we fail to simplify
a_4 = &x_3(D)->data;
b_5 = x_3(D) + 16;
_1 = b_5 - a_4;
together with the enabler handling ADDR_EXPR leafs in separate
stmts in match.pd the suggested patterns work.
PR tree-optimization/89317
* match.pd ((p + b) - &p->c -> b - offsetof(c)): New patterns.
* gcc.dg/tree-ssa/pr89317.c: New testcase.
Diffstat (limited to 'gcc')
| -rw-r--r-- | gcc/match.pd | 11 | ||||
| -rw-r--r-- | gcc/testsuite/gcc.dg/tree-ssa/pr89317.c | 13 |
2 files changed, 24 insertions, 0 deletions
diff --git a/gcc/match.pd b/gcc/match.pd index 046ea2c..ba83c69 100644 --- a/gcc/match.pd +++ b/gcc/match.pd @@ -2451,6 +2451,17 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT) (with { poly_int64 diff; } (if (ptr_difference_const (@0, @2, &diff)) (plus { build_int_cst_type (type, diff); } (convert (minus @1 @3)))))) +/* (p + b) - &p->d -> offsetof (*p, d) + b */ +(simplify + (pointer_diff (pointer_plus @0 @1) ADDR_EXPR@2) + (with { poly_int64 diff; } + (if (ptr_difference_const (@0, @2, &diff)) + (plus { build_int_cst_type (type, diff); } (convert @1))))) +(simplify + (pointer_diff ADDR_EXPR@0 (pointer_plus @1 @2)) + (with { poly_int64 diff; } + (if (ptr_difference_const (@0, @1, &diff)) + (minus { build_int_cst_type (type, diff); } (convert @2))))) /* Canonicalize (T *)(ptr - ptr-cst) to &MEM[ptr + -ptr-cst]. */ (simplify diff --git a/gcc/testsuite/gcc.dg/tree-ssa/pr89317.c b/gcc/testsuite/gcc.dg/tree-ssa/pr89317.c new file mode 100644 index 0000000..0d0a049 --- /dev/null +++ b/gcc/testsuite/gcc.dg/tree-ssa/pr89317.c @@ -0,0 +1,13 @@ +/* { dg-do compile } */ +/* { dg-options "-O -fdump-tree-ccp1" } */ + +struct b { int data[16]; }; + +int foo (struct b *x) +{ + int *a = x->data; + int *b = ((int*)x) + 4; + return b - a; +} + +/* { dg-final { scan-tree-dump "return 4;" "ccp1" } } */ |