Handle IFN_COND_MUL in tree-ssa-math-opts.c
This patch extends the FMA handling in tree-ssa-math-opts.c so
that it can cope with conditional multiplications as well as
unconditional multiplications. The addition or subtraction must then
have the same condition as the multiplication (at least for now).
E.g. we can currently fold:
(IFN_COND_ADD cond (mul x y) z fallback)
-> (IFN_COND_FMA cond x y z fallback)
This patch also allows:
(IFN_COND_ADD cond (IFN_COND_MUL cond x y ) z fallback)
-> (IFN_COND_FMA cond x y z fallback)
Tested on aarch64-linux-gnu, aarch64_be-elf and x86_64-linux-gnu.
OK to install?
Richard
2019-07-30 Richard Sandiford
gcc/
* tree-ssa-math-opts.c (convert_mult_to_fma): Add a mul_cond
parameter. When nonnull, make sure that the addition or subtraction
has the same condition.
(math_opts_dom_walker::after_dom_children): Try convert_mult_to_fma
for CFN_COND_MUL too.
gcc/testsuite/
* gcc.dg/vect/vect-cond-arith-7.c: New test.
Index: gcc/tree-ssa-math-opts.c
===
--- gcc/tree-ssa-math-opts.c2019-07-30 10:51:22.0 +0100
+++ gcc/tree-ssa-math-opts.c2019-07-30 10:51:51.827405171 +0100
@@ -3044,6 +3044,8 @@ last_fma_candidate_feeds_initial_phi (fm
/* Combine the multiplication at MUL_STMT with operands MULOP1 and MULOP2
with uses in additions and subtractions to form fused multiply-add
operations. Returns true if successful and MUL_STMT should be removed.
+ If MUL_COND is nonnull, the multiplication in MUL_STMT is conditional
+ on MUL_COND, otherwise it is unconditional.
If STATE indicates that we are deferring FMA transformation, that means
that we do not produce FMAs for basic blocks which look like:
@@ -3060,7 +3062,7 @@ last_fma_candidate_feeds_initial_phi (fm
static bool
convert_mult_to_fma (gimple *mul_stmt, tree op1, tree op2,
-fma_deferring_state *state)
+fma_deferring_state *state, tree mul_cond = NULL_TREE)
{
tree mul_result = gimple_get_lhs (mul_stmt);
tree type = TREE_TYPE (mul_result);
@@ -3174,6 +3176,9 @@ convert_mult_to_fma (gimple *mul_stmt, t
return false;
}
+ if (mul_cond && cond != mul_cond)
+ return false;
+
if (cond)
{
if (cond == result || else_value == result)
@@ -3785,38 +3790,48 @@ math_opts_dom_walker::after_dom_children
}
else if (is_gimple_call (stmt))
{
- tree fndecl = gimple_call_fndecl (stmt);
- if (fndecl && gimple_call_builtin_p (stmt, BUILT_IN_NORMAL))
+ switch (gimple_call_combined_fn (stmt))
{
- switch (DECL_FUNCTION_CODE (fndecl))
+ CASE_CFN_POW:
+ if (gimple_call_lhs (stmt)
+ && TREE_CODE (gimple_call_arg (stmt, 1)) == REAL_CST
+ && real_equal (&TREE_REAL_CST (gimple_call_arg (stmt, 1)),
+&dconst2)
+ && convert_mult_to_fma (stmt,
+ gimple_call_arg (stmt, 0),
+ gimple_call_arg (stmt, 0),
+ &fma_state))
{
- case BUILT_IN_POWF:
- case BUILT_IN_POW:
- case BUILT_IN_POWL:
- if (gimple_call_lhs (stmt)
- && TREE_CODE (gimple_call_arg (stmt, 1)) == REAL_CST
- && real_equal
- (&TREE_REAL_CST (gimple_call_arg (stmt, 1)),
- &dconst2)
- && convert_mult_to_fma (stmt,
- gimple_call_arg (stmt, 0),
- gimple_call_arg (stmt, 0),
- &fma_state))
- {
- unlink_stmt_vdef (stmt);
- if (gsi_remove (&gsi, true)
- && gimple_purge_dead_eh_edges (bb))
- *m_cfg_changed_p = true;
- release_defs (stmt);
- continue;
- }
- break;
+ unlink_stmt_vdef (stmt);
+ if (gsi_remove (&gsi, true)
+ && gimple_purge_dead_eh_edges (bb))
+ *m_cfg_changed_p = true;
+ release_defs (stmt);
+ continue;
+ }
+ break;
- default:;
+ case CFN_COND_MUL:
+ if (convert_mult_to_fma (stmt,
+ gimple_call_arg (stmt, 1),
+ gimple_call_arg (stmt, 2),
+ &fma_state,
+ gimple_call_arg (stmt, 0)))
+
+ {
+ gsi_remove (&gsi, true);
+ release_defs (stmt);
+ contin
Re: Handle IFN_COND_MUL in tree-ssa-math-opts.c
On Tue, Jul 30, 2019 at 12:01 PM Richard Sandiford
wrote:
>
> This patch extends the FMA handling in tree-ssa-math-opts.c so
> that it can cope with conditional multiplications as well as
> unconditional multiplications. The addition or subtraction must then
> have the same condition as the multiplication (at least for now).
>
> E.g. we can currently fold:
>
> (IFN_COND_ADD cond (mul x y) z fallback)
> -> (IFN_COND_FMA cond x y z fallback)
>
> This patch also allows:
>
> (IFN_COND_ADD cond (IFN_COND_MUL cond x y ) z fallback)
> -> (IFN_COND_FMA cond x y z fallback)
>
> Tested on aarch64-linux-gnu, aarch64_be-elf and x86_64-linux-gnu.
> OK to install?
OK.
> Richard
>
>
> 2019-07-30 Richard Sandiford
>
> gcc/
> * tree-ssa-math-opts.c (convert_mult_to_fma): Add a mul_cond
> parameter. When nonnull, make sure that the addition or subtraction
> has the same condition.
> (math_opts_dom_walker::after_dom_children): Try convert_mult_to_fma
> for CFN_COND_MUL too.
>
> gcc/testsuite/
> * gcc.dg/vect/vect-cond-arith-7.c: New test.
>
> Index: gcc/tree-ssa-math-opts.c
> ===
> --- gcc/tree-ssa-math-opts.c2019-07-30 10:51:22.0 +0100
> +++ gcc/tree-ssa-math-opts.c2019-07-30 10:51:51.827405171 +0100
> @@ -3044,6 +3044,8 @@ last_fma_candidate_feeds_initial_phi (fm
> /* Combine the multiplication at MUL_STMT with operands MULOP1 and MULOP2
> with uses in additions and subtractions to form fused multiply-add
> operations. Returns true if successful and MUL_STMT should be removed.
> + If MUL_COND is nonnull, the multiplication in MUL_STMT is conditional
> + on MUL_COND, otherwise it is unconditional.
>
> If STATE indicates that we are deferring FMA transformation, that means
> that we do not produce FMAs for basic blocks which look like:
> @@ -3060,7 +3062,7 @@ last_fma_candidate_feeds_initial_phi (fm
>
> static bool
> convert_mult_to_fma (gimple *mul_stmt, tree op1, tree op2,
> -fma_deferring_state *state)
> +fma_deferring_state *state, tree mul_cond = NULL_TREE)
> {
>tree mul_result = gimple_get_lhs (mul_stmt);
>tree type = TREE_TYPE (mul_result);
> @@ -3174,6 +3176,9 @@ convert_mult_to_fma (gimple *mul_stmt, t
> return false;
> }
>
> + if (mul_cond && cond != mul_cond)
> + return false;
> +
>if (cond)
> {
> if (cond == result || else_value == result)
> @@ -3785,38 +3790,48 @@ math_opts_dom_walker::after_dom_children
> }
>else if (is_gimple_call (stmt))
> {
> - tree fndecl = gimple_call_fndecl (stmt);
> - if (fndecl && gimple_call_builtin_p (stmt, BUILT_IN_NORMAL))
> + switch (gimple_call_combined_fn (stmt))
> {
> - switch (DECL_FUNCTION_CODE (fndecl))
> + CASE_CFN_POW:
> + if (gimple_call_lhs (stmt)
> + && TREE_CODE (gimple_call_arg (stmt, 1)) == REAL_CST
> + && real_equal (&TREE_REAL_CST (gimple_call_arg (stmt, 1)),
> +&dconst2)
> + && convert_mult_to_fma (stmt,
> + gimple_call_arg (stmt, 0),
> + gimple_call_arg (stmt, 0),
> + &fma_state))
> {
> - case BUILT_IN_POWF:
> - case BUILT_IN_POW:
> - case BUILT_IN_POWL:
> - if (gimple_call_lhs (stmt)
> - && TREE_CODE (gimple_call_arg (stmt, 1)) == REAL_CST
> - && real_equal
> - (&TREE_REAL_CST (gimple_call_arg (stmt, 1)),
> - &dconst2)
> - && convert_mult_to_fma (stmt,
> - gimple_call_arg (stmt, 0),
> - gimple_call_arg (stmt, 0),
> - &fma_state))
> - {
> - unlink_stmt_vdef (stmt);
> - if (gsi_remove (&gsi, true)
> - && gimple_purge_dead_eh_edges (bb))
> - *m_cfg_changed_p = true;
> - release_defs (stmt);
> - continue;
> - }
> - break;
> + unlink_stmt_vdef (stmt);
> + if (gsi_remove (&gsi, true)
> + && gimple_purge_dead_eh_edges (bb))
> + *m_cfg_changed_p = true;
> + release_defs (stmt);
> + continue;
> + }
> + break;
>
> - default:;
> + case CFN_COND_MUL:
> + if (convert_mult_to_fma (stmt,
> + gimple_call_arg (stmt, 1),
> +
