| Message ID | 20231024064557.213050-1-pinskia@gmail.com |
|---|---|
| State | New |
| Headers | show |
| Series | [PATCHv2] Improve factor_out_conditional_operation for conversions and constants | expand |
On Tue, Oct 24, 2023 at 8:45 AM Andrew Pinski <pinskia@gmail.com> wrote: > > In the case of a NOP conversion (precisions of the 2 types are equal), > factoring out the conversion can be done even if int_fits_type_p returns > false and even when the conversion is defined by a statement inside the > conditional. Since it is a NOP conversion there is no zero/sign extending > happening which is why it is ok to be done here; we were trying to prevent > an extra sign/zero extend from being moved away from definition which no-op > conversions are not. > > Bootstrapped and tested on x86_64-linux-gnu with no regressions. OK. > gcc/ChangeLog: > > PR tree-optimization/104376 > PR tree-optimization/101541 > * tree-ssa-phiopt.cc (factor_out_conditional_operation): > Allow nop conversions even if it is defined by a statement > inside the conditional. > > gcc/testsuite/ChangeLog: > > PR tree-optimization/101541 > * gcc.dg/tree-ssa/phi-opt-39.c: New test. > --- > gcc/testsuite/gcc.dg/tree-ssa/phi-opt-39.c | 43 ++++++++++++++++++++++ > gcc/tree-ssa-phiopt.cc | 16 ++++++-- > 2 files changed, 56 insertions(+), 3 deletions(-) > create mode 100644 gcc/testsuite/gcc.dg/tree-ssa/phi-opt-39.c > > diff --git a/gcc/testsuite/gcc.dg/tree-ssa/phi-opt-39.c b/gcc/testsuite/gcc.dg/tree-ssa/phi-opt-39.c > new file mode 100644 > index 00000000000..6b6006a96db > --- /dev/null > +++ b/gcc/testsuite/gcc.dg/tree-ssa/phi-opt-39.c > @@ -0,0 +1,43 @@ > +/* { dg-options "-O2 -fdump-tree-phiopt" } */ > + > +unsigned f0(int A) > +{ > +// A == 0? A : -A same as -A > + if (A == 0) return A; > + return -A; > +} > + > +unsigned f1(int A) > +{ > +// A != 0? A : -A same as A > + if (A != 0) return A; > + return -A; > +} > +unsigned f2(int A) > +{ > +// A >= 0? A : -A same as abs (A) > + if (A >= 0) return A; > + return -A; > +} > +unsigned f3(int A) > +{ > +// A > 0? A : -A same as abs (A) > + if (A > 0) return A; > + return -A; > +} > +unsigned f4(int A) > +{ > +// A <= 0? A : -A same as -abs (A) > + if (A <= 0) return A; > + return -A; > +} > +unsigned f5(int A) > +{ > +// A < 0? A : -A same as -abs (A) > + if (A < 0) return A; > + return -A; > +} > + > +/* f4 and f5 are not allowed to be optimized in early phi-opt. */ > +/* { dg-final { scan-tree-dump-times "if" 2 "phiopt1" } } */ > +/* { dg-final { scan-tree-dump-not "if" "phiopt2" } } */ > diff --git a/gcc/tree-ssa-phiopt.cc b/gcc/tree-ssa-phiopt.cc > index 312a6f9082b..bb55a4fba33 100644 > --- a/gcc/tree-ssa-phiopt.cc > +++ b/gcc/tree-ssa-phiopt.cc > @@ -310,7 +310,9 @@ factor_out_conditional_operation (edge e0, edge e1, gphi *phi, > return NULL; > /* If arg1 is an INTEGER_CST, fold it to new type. */ > if (INTEGRAL_TYPE_P (TREE_TYPE (new_arg0)) > - && int_fits_type_p (arg1, TREE_TYPE (new_arg0))) > + && (int_fits_type_p (arg1, TREE_TYPE (new_arg0)) > + || (TYPE_PRECISION (TREE_TYPE (new_arg0)) > + == TYPE_PRECISION (TREE_TYPE (arg1))))) > { > if (gimple_assign_cast_p (arg0_def_stmt)) > { > @@ -322,8 +324,12 @@ factor_out_conditional_operation (edge e0, edge e1, gphi *phi, > if arg0_def_stmt is the only non-debug stmt in > its basic block, because then it is possible this > could enable further optimizations (minmax replacement > - etc.). See PR71016. */ > - if (new_arg0 != gimple_cond_lhs (cond_stmt) > + etc.). See PR71016. > + Note no-op conversions don't have this issue as > + it will not generate any zero/sign extend in that case. */ > + if ((TYPE_PRECISION (TREE_TYPE (new_arg0)) > + != TYPE_PRECISION (TREE_TYPE (arg1))) > + && new_arg0 != gimple_cond_lhs (cond_stmt) > && new_arg0 != gimple_cond_rhs (cond_stmt) > && gimple_bb (arg0_def_stmt) == e0->src) > { > @@ -354,6 +360,10 @@ factor_out_conditional_operation (edge e0, edge e1, gphi *phi, > return NULL; > } > new_arg1 = fold_convert (TREE_TYPE (new_arg0), arg1); > + > + /* Drop the overlow that fold_convert might add. */ > + if (TREE_OVERFLOW (new_arg1)) > + new_arg1 = drop_tree_overflow (new_arg1); > } > else > return NULL; > -- > 2.34.1 >
diff --git a/gcc/testsuite/gcc.dg/tree-ssa/phi-opt-39.c b/gcc/testsuite/gcc.dg/tree-ssa/phi-opt-39.c new file mode 100644 index 00000000000..6b6006a96db --- /dev/null +++ b/gcc/testsuite/gcc.dg/tree-ssa/phi-opt-39.c @@ -0,0 +1,43 @@ +/* { dg-options "-O2 -fdump-tree-phiopt" } */ + +unsigned f0(int A) +{ +// A == 0? A : -A same as -A + if (A == 0) return A; + return -A; +} + +unsigned f1(int A) +{ +// A != 0? A : -A same as A + if (A != 0) return A; + return -A; +} +unsigned f2(int A) +{ +// A >= 0? A : -A same as abs (A) + if (A >= 0) return A; + return -A; +} +unsigned f3(int A) +{ +// A > 0? A : -A same as abs (A) + if (A > 0) return A; + return -A; +} +unsigned f4(int A) +{ +// A <= 0? A : -A same as -abs (A) + if (A <= 0) return A; + return -A; +} +unsigned f5(int A) +{ +// A < 0? A : -A same as -abs (A) + if (A < 0) return A; + return -A; +} + +/* f4 and f5 are not allowed to be optimized in early phi-opt. */ +/* { dg-final { scan-tree-dump-times "if" 2 "phiopt1" } } */ +/* { dg-final { scan-tree-dump-not "if" "phiopt2" } } */ diff --git a/gcc/tree-ssa-phiopt.cc b/gcc/tree-ssa-phiopt.cc index 312a6f9082b..bb55a4fba33 100644 --- a/gcc/tree-ssa-phiopt.cc +++ b/gcc/tree-ssa-phiopt.cc @@ -310,7 +310,9 @@ factor_out_conditional_operation (edge e0, edge e1, gphi *phi, return NULL; /* If arg1 is an INTEGER_CST, fold it to new type. */ if (INTEGRAL_TYPE_P (TREE_TYPE (new_arg0)) - && int_fits_type_p (arg1, TREE_TYPE (new_arg0))) + && (int_fits_type_p (arg1, TREE_TYPE (new_arg0)) + || (TYPE_PRECISION (TREE_TYPE (new_arg0)) + == TYPE_PRECISION (TREE_TYPE (arg1))))) { if (gimple_assign_cast_p (arg0_def_stmt)) { @@ -322,8 +324,12 @@ factor_out_conditional_operation (edge e0, edge e1, gphi *phi, if arg0_def_stmt is the only non-debug stmt in its basic block, because then it is possible this could enable further optimizations (minmax replacement - etc.). See PR71016. */ - if (new_arg0 != gimple_cond_lhs (cond_stmt) + etc.). See PR71016. + Note no-op conversions don't have this issue as + it will not generate any zero/sign extend in that case. */ + if ((TYPE_PRECISION (TREE_TYPE (new_arg0)) + != TYPE_PRECISION (TREE_TYPE (arg1))) + && new_arg0 != gimple_cond_lhs (cond_stmt) && new_arg0 != gimple_cond_rhs (cond_stmt) && gimple_bb (arg0_def_stmt) == e0->src) { @@ -354,6 +360,10 @@ factor_out_conditional_operation (edge e0, edge e1, gphi *phi, return NULL; } new_arg1 = fold_convert (TREE_TYPE (new_arg0), arg1); + + /* Drop the overlow that fold_convert might add. */ + if (TREE_OVERFLOW (new_arg1)) + new_arg1 = drop_tree_overflow (new_arg1); } else return NULL;