https://gcc.gnu.org/g:3d102b7a40bd179c93eccc31b74f95c69f81f45e
commit r16-4603-g3d102b7a40bd179c93eccc31b74f95c69f81f45e Author: Andrew MacLeod <[email protected]> Date: Tue Oct 21 16:05:22 2025 -0400 Create and apply bitmasks for truncating casts. When folding a cast, we were not applying the bitmask if we reached a VARYING result. We were also not creating a bitmask to represent the lower bits of a truncating cast in op1_range. So GORI was losing bits. PR tree-optimization/118254 PR tree-optimization/114331 gcc/ * range-op.cc (operator_cast::fold_range): When VARYING is reached, update the bitmask if we reach VARYING. (operator_cast::op1_range): For truncating casts, create a bitmask bit in LHS. gcc/testsuite/ * gcc.dg/pr114331.c: New. * gcc.dg/pr118254.c: New. Diff: --- gcc/range-op.cc | 22 +++++++++++++++++++++- gcc/testsuite/gcc.dg/pr114331.c | 20 ++++++++++++++++++++ gcc/testsuite/gcc.dg/pr118254.c | 34 ++++++++++++++++++++++++++++++++++ 3 files changed, 75 insertions(+), 1 deletion(-) diff --git a/gcc/range-op.cc b/gcc/range-op.cc index 1f91066a44e7..762fd349e5f7 100644 --- a/gcc/range-op.cc +++ b/gcc/range-op.cc @@ -3103,8 +3103,9 @@ operator_cast::fold_range (irange &r, tree type ATTRIBUTE_UNUSED, int_range_max tmp; fold_pair (tmp, x, inner, outer); r.union_ (tmp); + // If we hit varying, go update the bitmask. if (r.varying_p ()) - return true; + break; } update_bitmask (r, inner, outer); @@ -3204,6 +3205,25 @@ operator_cast::op1_range (irange &r, tree type, } // And intersect with any known value passed in the extra operand. r.intersect (op2); + if (r.undefined_p ()) + return true; + + // Now create a bitmask indicating that the lower bit must match the + // bits in the LHS. Zero-extend LHS bitmask to precision of op1. + irange_bitmask bm = lhs.get_bitmask (); + wide_int mask = wide_int::from (bm.mask (), TYPE_PRECISION (type), + UNSIGNED); + wide_int value = wide_int::from (bm.value (), TYPE_PRECISION (type), + UNSIGNED); + + // Set then additonal unknown bits in mask. + wide_int lim = wi::mask (TYPE_PRECISION (lhs_type), true, + TYPE_PRECISION (type)); + mask = mask | lim; + + // Now set the new bitmask for the range. + irange_bitmask new_bm (value, mask); + r.update_bitmask (new_bm); return true; } diff --git a/gcc/testsuite/gcc.dg/pr114331.c b/gcc/testsuite/gcc.dg/pr114331.c new file mode 100644 index 000000000000..e93289e651b0 --- /dev/null +++ b/gcc/testsuite/gcc.dg/pr114331.c @@ -0,0 +1,20 @@ +/* { dg-do compile } */ +/* { dg-options "-O2 -fdump-tree-optimized" } */ + +int src(int num) { + switch((short)num){ + case 111: + /* Should fold to 110. */ + return num & 0xfffe; + case 267: + case 204: + case 263: + return 0; + default: + return 0; + } +} + + +/* { dg-final { scan-tree-dump "110" "optimized" } } */ + diff --git a/gcc/testsuite/gcc.dg/pr118254.c b/gcc/testsuite/gcc.dg/pr118254.c new file mode 100644 index 000000000000..5a0553ba6f95 --- /dev/null +++ b/gcc/testsuite/gcc.dg/pr118254.c @@ -0,0 +1,34 @@ +/* { dg-do compile } */ +/* { dg-options "-O2 -fdump-tree-evrp" } */ + +void foo(void); +int il=1000; + +int m1(void) +{ + short t = il; + unsigned t1 = t; + if (t1 == 0) { + char b = t1; + if (b != 1) + return 0; + foo(); + } + return 0; +} + +int m2(void) +{ + short t = il; + unsigned t1 = t; + if (t1 == 0) { + char b = il; + if (b != 1) + return 0; + foo(); + } + return 0; +} + +/* { dg-final { scan-tree-dump-not "foo" "evrp" } } */ +
