https://gcc.gnu.org/g:230d950810f378a16c47ab981e0b9cf88b700622
commit r17-4133-g230d950810f378a16c47ab981e0b9cf88b700622 Author: Andrea Pinski <[email protected]> Date: Tue Aug 25 13:28:49 2026 -0700 phiopt/cselim: Support constants for cond_store_replacement_limited [PR127052] So when I wrote this code I limited the middle store to only be a SSA name. This is too limited and we reject constants which the full cselim can handle just fine. This extends the check to support gimple min invariants too. Instead of the check for ssa name, reject clobbers instead. Changes since v1: * v2: Change the checks to reject clobbers instead of checking for min invariant/ssa names. Bootstrapped and tested on x86_64-linux-gnu. PR tree-optimization/127052 gcc/ChangeLog: * tree-ssa-phiopt.cc (cond_store_replacement_limited): Reject clobbers for the middle bb store. And Remove the check on ssa name for the rhs of the middle bb store. gcc/testsuite/ChangeLog: * gcc.dg/tree-ssa/cselim-6.c: New test. * gcc.dg/tree-ssa/cselim-7.c: New test. Signed-off-by: Andrea Pinski <[email protected]> Diff: --- gcc/testsuite/gcc.dg/tree-ssa/cselim-6.c | 17 +++++++++++++++++ gcc/testsuite/gcc.dg/tree-ssa/cselim-7.c | 18 ++++++++++++++++++ gcc/tree-ssa-phiopt.cc | 6 +++--- 3 files changed, 38 insertions(+), 3 deletions(-) diff --git a/gcc/testsuite/gcc.dg/tree-ssa/cselim-6.c b/gcc/testsuite/gcc.dg/tree-ssa/cselim-6.c new file mode 100644 index 000000000000..54d1446ecd74 --- /dev/null +++ b/gcc/testsuite/gcc.dg/tree-ssa/cselim-6.c @@ -0,0 +1,17 @@ +/* { dg-do compile } */ +/* { dg-options "-O2 -ftree-cselim -fdump-tree-phiopt1-details" } */ +/* PR tree-optimization/127052 */ + +int *sink(int*); +void f(int a, int c, int d, int *e) +{ + e = sink(&a); + a = d; + c = *e; + c += a; + if (c) + a = 0; + sink(&a); +} + +/* { dg-final { scan-tree-dump "Conditional store replacement" "phiopt1" } } */ diff --git a/gcc/testsuite/gcc.dg/tree-ssa/cselim-7.c b/gcc/testsuite/gcc.dg/tree-ssa/cselim-7.c new file mode 100644 index 000000000000..8db89c24b569 --- /dev/null +++ b/gcc/testsuite/gcc.dg/tree-ssa/cselim-7.c @@ -0,0 +1,18 @@ +/* { dg-do compile } */ +/* { dg-options "-O2 -ftree-cselim -fdump-tree-phiopt1-details" } */ +/* PR tree-optimization/127052 */ + +void sink(int*); + +int f(int b) +{ + int a; + sink(&a); + a = b; + if (a) + a = 0; + return a; +} + + +/* { dg-final { scan-tree-dump "Conditional store replacement" "phiopt1" } } */ diff --git a/gcc/tree-ssa-phiopt.cc b/gcc/tree-ssa-phiopt.cc index 7203f4d29c88..fbb4ec545e6f 100644 --- a/gcc/tree-ssa-phiopt.cc +++ b/gcc/tree-ssa-phiopt.cc @@ -3601,7 +3601,9 @@ cond_store_replacement_limited (basic_block middle_bb, basic_block join_bb, if (!store_middle || !gimple_assign_single_p (store_middle) - || gimple_has_volatile_ops (store_middle)) + || gimple_has_volatile_ops (store_middle) + // Rejects clobbers too. + || gimple_clobber_p (store_middle)) return false; locus = gimple_location (store_middle); @@ -3611,8 +3613,6 @@ cond_store_replacement_limited (basic_block middle_bb, basic_block join_bb, && !DECL_P (lhs)) || !is_gimple_reg_type (TREE_TYPE (lhs))) return false; - if (TREE_CODE (rhs) != SSA_NAME) - return false; /* Three cases that can be handled: 1) the lhs is stored to right before the condition.
