If we defer an FMA creation the code tries to determine the order of the
operands before deferring. To do this it compares the operands against the
result expression (which should contain the multiplication expression).
However the multiply might be wrapped in a conversion. This change has us strip
one level of conversion (the most that convert_mult_to_fma) supports handling
and only then do the comparison.
We cannot strip ops[0] and ops[1] and store them stripped since after the
deferrence, if we create an FMA we need to know the original types and
convert_mult_to_fma handles the conversions during FMA creation anyway.
There's probably a similar helper to strip_nop_view_converts but I couldn't
find one, since many of the stripping helpers are recursive or don't support
stripping VIEW_CONVERTS.
Bootstrapped Regtested on aarch64-none-linux-gnu,
arm-none-linux-gnueabihf, x86_64-pc-linux-gnu
-m32, -m64 and no issues.
Ok for master?
Thanks,
Tamar
gcc/ChangeLog:
PR tree-optimization/123897
* tree-ssa-math-opts.cc (strip_nop_view_converts): New.
(convert_mult_to_fma): Use it.
gcc/testsuite/ChangeLog:
PR tree-optimization/123897
* gcc.target/aarch64/sve/pr123898.c: New test.
---
diff --git a/gcc/testsuite/gcc.target/aarch64/sve/pr123898.c
b/gcc/testsuite/gcc.target/aarch64/sve/pr123898.c
new file mode 100644
index
0000000000000000000000000000000000000000..a5741d5058e81b8c34bcfacca5f456bc015308a1
--- /dev/null
+++ b/gcc/testsuite/gcc.target/aarch64/sve/pr123898.c
@@ -0,0 +1,17 @@
+/* { dg-do compile } */
+/* { dg-additional-options "-O2 --param avoid-fma-max-bits=512 -march=armv9-a
-msve-vector-bits=256 -fdump-tree-widening_mul" } */
+
+typedef __attribute__((__vector_size__(32))) char A;
+typedef __attribute__((__vector_size__(32))) signed char D;
+
+A c;
+char x;
+
+void
+foo(D d)
+{
+ d *= x;
+ c += (A)d;
+}
+
+/* { dg-final { scan-tree-dump-times "\.FMA" 1 "widening_mul" } } */
diff --git a/gcc/tree-ssa-math-opts.cc b/gcc/tree-ssa-math-opts.cc
index
9522532b7fc64678c57e9b72342940e7cac9d801..24f01c8359cbe9cdb06ea6192bb5baf9a7da92ee
100644
--- a/gcc/tree-ssa-math-opts.cc
+++ b/gcc/tree-ssa-math-opts.cc
@@ -3353,6 +3353,29 @@ last_fma_candidate_feeds_initial_phi
(fma_deferring_state *state,
return false;
}
+/* If ARG is a view_convert that only changes the sign then strip the outer
+ conversion away. It does not strip conversions recursively. Otherwise
+ return ARG. */
+
+static tree
+strip_nop_view_converts (tree arg)
+{
+ if (TREE_CODE (arg) != SSA_NAME)
+ return arg;
+
+ gimple *assign = SSA_NAME_DEF_STMT (arg);
+ tree lhs_type, var;
+ if (gimple_assign_cast_p (assign)
+ && (var = gimple_assign_rhs1 (assign))
+ && TREE_CODE (var) != SSA_NAME
+ && (var = TREE_OPERAND (var, 0))
+ && (lhs_type = TREE_TYPE (var))
+ && tree_nop_conversion_p (lhs_type, TREE_TYPE (arg)))
+ return var;
+
+ return arg;
+}
+
/* 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.
@@ -3613,11 +3636,11 @@ convert_mult_to_fma (gimple *mul_stmt, tree op1, tree
op2,
{
gcc_checking_assert (!state->m_initial_phi);
gphi *phi;
- if (ops[0] == result)
+ if (strip_nop_view_converts (ops[0]) == result)
phi = result_of_phi (ops[1]);
else
{
- gcc_assert (ops[1] == result);
+ gcc_assert (strip_nop_view_converts (ops[1]) == result);
phi = result_of_phi (ops[0]);
}
--
diff --git a/gcc/testsuite/gcc.target/aarch64/sve/pr123898.c b/gcc/testsuite/gcc.target/aarch64/sve/pr123898.c
new file mode 100644
index 0000000000000000000000000000000000000000..a5741d5058e81b8c34bcfacca5f456bc015308a1
--- /dev/null
+++ b/gcc/testsuite/gcc.target/aarch64/sve/pr123898.c
@@ -0,0 +1,17 @@
+/* { dg-do compile } */
+/* { dg-additional-options "-O2 --param avoid-fma-max-bits=512 -march=armv9-a -msve-vector-bits=256 -fdump-tree-widening_mul" } */
+
+typedef __attribute__((__vector_size__(32))) char A;
+typedef __attribute__((__vector_size__(32))) signed char D;
+
+A c;
+char x;
+
+void
+foo(D d)
+{
+ d *= x;
+ c += (A)d;
+}
+
+/* { dg-final { scan-tree-dump-times "\.FMA" 1 "widening_mul" } } */
diff --git a/gcc/tree-ssa-math-opts.cc b/gcc/tree-ssa-math-opts.cc
index 9522532b7fc64678c57e9b72342940e7cac9d801..24f01c8359cbe9cdb06ea6192bb5baf9a7da92ee 100644
--- a/gcc/tree-ssa-math-opts.cc
+++ b/gcc/tree-ssa-math-opts.cc
@@ -3353,6 +3353,29 @@ last_fma_candidate_feeds_initial_phi (fma_deferring_state *state,
return false;
}
+/* If ARG is a view_convert that only changes the sign then strip the outer
+ conversion away. It does not strip conversions recursively. Otherwise
+ return ARG. */
+
+static tree
+strip_nop_view_converts (tree arg)
+{
+ if (TREE_CODE (arg) != SSA_NAME)
+ return arg;
+
+ gimple *assign = SSA_NAME_DEF_STMT (arg);
+ tree lhs_type, var;
+ if (gimple_assign_cast_p (assign)
+ && (var = gimple_assign_rhs1 (assign))
+ && TREE_CODE (var) != SSA_NAME
+ && (var = TREE_OPERAND (var, 0))
+ && (lhs_type = TREE_TYPE (var))
+ && tree_nop_conversion_p (lhs_type, TREE_TYPE (arg)))
+ return var;
+
+ return arg;
+}
+
/* 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.
@@ -3613,11 +3636,11 @@ convert_mult_to_fma (gimple *mul_stmt, tree op1, tree op2,
{
gcc_checking_assert (!state->m_initial_phi);
gphi *phi;
- if (ops[0] == result)
+ if (strip_nop_view_converts (ops[0]) == result)
phi = result_of_phi (ops[1]);
else
{
- gcc_assert (ops[1] == result);
+ gcc_assert (strip_nop_view_converts (ops[1]) == result);
phi = result_of_phi (ops[0]);
}
