https://gcc.gnu.org/g:698e0ec89bc0960e074d2222208bffe47f5addd9
commit r15-3992-g698e0ec89bc0960e074d2222208bffe47f5addd9
Author: Andrew Pinski <quic_apin...@quicinc.com>
Date: Mon Sep 30 16:44:44 2024 +0000
phi-opt: Improve factor heurstic with constants and conversions from bool
[PR116890]
Take:
```
if (t_3(D) != 0)
goto <bb 3>;
else
goto <bb 4>;
<bb 3>
_8 = c_4(D) != 0;
_9 = (int) _8;
<bb 4>
# e_2 = PHI <_9(3), 0(2)>
```
We should factor out the conversion here as that will allow a simplfication
to
`(t_3 != 0) & (c_4 != 0)`. Unlike most other types; `a ? b : CST` will
simplify
for boolean result type to either `a | b` or `a & b` so allowing this
conversion
for all operations will be always profitable.
Bootstrapped and tested on x86_64-linux-gnu with no regressions.
Note on the phi-opt-7.c testcase change, we are now able to optimize this
and remove the if due to the factoring out now so this is an improvement.
PR tree-optimization/116890
gcc/ChangeLog:
* tree-ssa-phiopt.cc (factor_out_conditional_operation): Conversions
from bool is also should be considered as wanting to happen.
gcc/testsuite/ChangeLog:
* gcc.dg/tree-ssa/phi-opt-7.c: Update testcase for no ifs left.
* gcc.dg/tree-ssa/phi-opt-42.c: New test.
* gcc.dg/tree-ssa/phi-opt-43.c: New test.
Signed-off-by: Andrew Pinski <quic_apin...@quicinc.com>
Diff:
---
gcc/testsuite/gcc.dg/tree-ssa/phi-opt-42.c | 19 +++++++++++++++++++
gcc/testsuite/gcc.dg/tree-ssa/phi-opt-43.c | 19 +++++++++++++++++++
gcc/testsuite/gcc.dg/tree-ssa/phi-opt-7.c | 6 +++---
gcc/tree-ssa-phiopt.cc | 10 +++++++++-
4 files changed, 50 insertions(+), 4 deletions(-)
diff --git a/gcc/testsuite/gcc.dg/tree-ssa/phi-opt-42.c
b/gcc/testsuite/gcc.dg/tree-ssa/phi-opt-42.c
new file mode 100644
index 000000000000..62556945159c
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/tree-ssa/phi-opt-42.c
@@ -0,0 +1,19 @@
+/* { dg-do compile } */
+/* { dg-options "-O1 -fdump-tree-optimized" } */
+
+/* PR tree-optimization/116890 */
+
+int f(int a, int b, int c)
+{
+ int x;
+ if (c) x = a == 0;
+ else x = 0;
+ return x;
+}
+
+
+/* The if should have been removed as the the conversion from bool to int
should have been factored out. */
+/* { dg-final { scan-tree-dump-not "if" "optimized" } }*/
+/* { dg-final { scan-tree-dump-times "\[^\r\n\]*_\[0-9\]* = a_\[0-9\]*.D. ==
0" 1 "optimized" } } */
+/* { dg-final { scan-tree-dump-times "\[^\r\n\]*_\[0-9\]* = c_\[0-9\]*.D. !=
0" 1 "optimized" } } */
+
diff --git a/gcc/testsuite/gcc.dg/tree-ssa/phi-opt-43.c
b/gcc/testsuite/gcc.dg/tree-ssa/phi-opt-43.c
new file mode 100644
index 000000000000..1d16f283f27b
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/tree-ssa/phi-opt-43.c
@@ -0,0 +1,19 @@
+/* { dg-do compile } */
+/* { dg-options "-O1 -fdump-tree-optimized" } */
+
+/* PR tree-optimization/116890 */
+
+int f(_Bool a, _Bool b, int c)
+{
+ int x;
+ if (c) x = a & b;
+ else x = 0;
+ return x;
+}
+
+
+/* The if should have been removed as the the conversion from bool to int
should have been factored out. */
+/* { dg-final { scan-tree-dump-not "if" "optimized" } }*/
+/* { dg-final { scan-tree-dump-times "\[^\r\n\]*_\[0-9\]* = a_\[0-9\]*.D. &
b_\[0-9\]*.D." 1 "optimized" } } */
+/* { dg-final { scan-tree-dump-times "\[^\r\n\]*_\[0-9\]* = c_\[0-9\]*.D. !=
0" 1 "optimized" } } */
+
diff --git a/gcc/testsuite/gcc.dg/tree-ssa/phi-opt-7.c
b/gcc/testsuite/gcc.dg/tree-ssa/phi-opt-7.c
index 51e1f6dfa755..3ee43e55692e 100644
--- a/gcc/testsuite/gcc.dg/tree-ssa/phi-opt-7.c
+++ b/gcc/testsuite/gcc.dg/tree-ssa/phi-opt-7.c
@@ -15,8 +15,8 @@ int f(int t, int c)
return g(d,e);
}
-/* There should be one ifs as one of them should be changed into
- a conditional and the other should be there still. */
-/* { dg-final { scan-tree-dump-times "if" 1 "optimized" } }*/
+/* There should be no ifs as this is converted into `(t != 0) & (c != 0)`.
+/* { dg-final { scan-tree-dump-not "if" "optimized" } }*/
/* { dg-final { scan-tree-dump-times "\[^\r\n\]*_\[0-9\]* = c_\[0-9\]*.D. !=
0" 1 "optimized" } } */
+/* { dg-final { scan-tree-dump-times "\[^\r\n\]*_\[0-9\]* = t_\[0-9\]*.D. !=
0" 1 "optimized" } } */
diff --git a/gcc/tree-ssa-phiopt.cc b/gcc/tree-ssa-phiopt.cc
index d43832b390ba..bd7f9607eb9a 100644
--- a/gcc/tree-ssa-phiopt.cc
+++ b/gcc/tree-ssa-phiopt.cc
@@ -345,9 +345,17 @@ factor_out_conditional_operation (edge e0, edge e1, gphi
*phi,
if (gassign *assign = dyn_cast <gassign *> (stmt))
{
tree lhs = gimple_assign_lhs (assign);
+ tree lhst = TREE_TYPE (lhs);
enum tree_code ass_code
= gimple_assign_rhs_code (assign);
- if (ass_code != MAX_EXPR && ass_code != MIN_EXPR)
+ if (ass_code != MAX_EXPR && ass_code != MIN_EXPR
+ /* Conversions from boolean like types is ok
+ as `a?1:b` and `a?0:b` will always simplify
+ to `a & b` or `a | b`.
+ See PR 116890. */
+ && !(INTEGRAL_TYPE_P (lhst)
+ && TYPE_UNSIGNED (lhst)
+ && TYPE_PRECISION (lhst) == 1))
return NULL;
if (lhs != gimple_assign_rhs1 (arg0_def_stmt))
return NULL;
