MATCH: [PR109424] Simplify min/max of boolean arguments

This is version 2 of https://gcc.gnu.org/pipermail/gcc-patches/2021-August/577394.html
which does not depend on adding gimple_truth_valued_p at this point.
Instead will use zero_one_valued_p which is already used for mult simplifications
to make sure that we only have [0,1] rather having the mistake of maybe having [-1,0]
as the range for signed bools.

This shows up in a few places in GCC itself but only at -O1, we miss the min/max conversion
because of PR 107888 (which I will be testing seperately).

OK? Bootstrapped and tested on x86_64-linux-gnu with no regressions.

Thanks,
Andrew Pinski

	PR tree-optimization/109424

gcc/ChangeLog:

	* match.pd: Add patterns for min/max of zero_one_valued
	values to `&`/`|`.

gcc/testsuite/ChangeLog:

	* gcc.dg/tree-ssa/bool-12.c: New test.
	* gcc.dg/tree-ssa/bool-13.c: New test.
	* gcc.dg/tree-ssa/minmax-20.c: New test.
	* gcc.dg/tree-ssa/minmax-21.c: New test.

5 files changed, 145 insertions, 0 deletions

diff --git a/gcc/match.pd b/gcc/match.pd
index b025fb8..30ffdfc 100644
--- a/gcc/match.pd
+++ b/gcc/match.pd
@@ -7439,6 +7439,14 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
        && TREE_CODE (@0) != INTEGER_CST)
    (op @0 (ext @1 @2)))))
 
+/* Max<bool0, bool1> -> bool0 | bool1
+   Min<bool0, bool1> -> bool0 & bool1 */
+(for op    (max     min)
+     logic (bit_ior bit_and)
+ (simplify
+  (op zero_one_valued_p@0 zero_one_valued_p@1)
+  (logic @0 @1)))
+
 /* signbit(x) != 0 ? -x : x -> abs(x)
    signbit(x) == 0 ? -x : x -> -abs(x) */
 (for sign (SIGNBIT)
diff --git a/gcc/testsuite/gcc.dg/tree-ssa/bool-12.c b/gcc/testsuite/gcc.dg/tree-ssa/bool-12.c
new file mode 100644
index 0000000..e62594e
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/tree-ssa/bool-12.c
@@ -0,0 +1,44 @@
+/* { dg-do compile } */
+/* { dg-options "-O1 -fdump-tree-optimized -fdump-tree-original -fdump-tree-phiopt1 -fdump-tree-forwprop2" } */
+#define bool _Bool
+int maxbool(bool ab, bool bb)
+{
+  int a = ab;
+  int b = bb;
+  int c;
+  if (a > b)
+    c = a;
+  else
+    c = b;
+  return c;
+}
+int minbool(bool ab, bool bb)
+{
+  int a = ab;
+  int b = bb;
+  int c;
+  if (a < b)
+    c = a;
+  else
+    c = b;
+  return c;
+}
+/* In Original, we should still have the if form as that is what is written. */
+/* { dg-final { scan-tree-dump-times "MAX_EXPR" 0 "original" } } */
+/* { dg-final { scan-tree-dump-times "MIN_EXPR" 0 "original" } } */
+/* { dg-final { scan-tree-dump-times "if " 2 "original" } } */
+
+/* PHI-OPT1 should have converted it into min/max */
+/* { dg-final { scan-tree-dump-times "MAX_EXPR" 1 "phiopt1" } } */
+/* { dg-final { scan-tree-dump-times "MIN_EXPR" 1 "phiopt1" } } */
+/* { dg-final { scan-tree-dump-times "if " 0 "phiopt1" } } */
+
+/* Forwprop2 (after ccp) will convert it into &\| */
+/* { dg-final { scan-tree-dump-times "MAX_EXPR" 0 "forwprop2" } } */
+/* { dg-final { scan-tree-dump-times "MIN_EXPR" 0 "forwprop2" } } */
+/* { dg-final { scan-tree-dump-times "if " 0 "forwprop2" } } */
+
+/* By optimize there should be no min/max nor if  */
+/* { dg-final { scan-tree-dump-times "MAX_EXPR" 0 "optimized" } } */
+/* { dg-final { scan-tree-dump-times "MIN_EXPR" 0 "optimized" } } */
+/* { dg-final { scan-tree-dump-times "if " 0 "optimized" } } */
diff --git a/gcc/testsuite/gcc.dg/tree-ssa/bool-13.c b/gcc/testsuite/gcc.dg/tree-ssa/bool-13.c
new file mode 100644
index 0000000..438f15a
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/tree-ssa/bool-13.c
@@ -0,0 +1,38 @@
+/* { dg-do compile } */
+/* { dg-options "-O1 -fdump-tree-optimized -fdump-tree-original -fdump-tree-phiopt1 -fdump-tree-forwprop2" } */
+#define bool _Bool
+int maxbool(bool ab, bool bb)
+{
+  int a = ab;
+  int b = bb;
+  int c;
+  c = a > b ? a : b;
+  return c;
+}
+int minbool(bool ab, bool bb)
+{
+  int a = ab;
+  int b = bb;
+  int c;
+  c = a < b ? a : b;
+  return c;
+}
+/* In Original, we should still have the min/max form as that is what is written. */
+/* { dg-final { scan-tree-dump-times "MAX_EXPR" 1 "original" } } */
+/* { dg-final { scan-tree-dump-times "MIN_EXPR" 1 "original" } } */
+/* { dg-final { scan-tree-dump-times "if " 0 "original" } } */
+
+/* PHI-OPT1 should have kept it as min/max. */
+/* { dg-final { scan-tree-dump-times "MAX_EXPR" 1 "phiopt1" } } */
+/* { dg-final { scan-tree-dump-times "MIN_EXPR" 1 "phiopt1" } } */
+/* { dg-final { scan-tree-dump-times "if " 0 "phiopt1" } } */
+
+/* Forwprop2 (after ccp) will convert it into &\| */
+/* { dg-final { scan-tree-dump-times "MAX_EXPR" 0 "forwprop2" } } */
+/* { dg-final { scan-tree-dump-times "MIN_EXPR" 0 "forwprop2" } } */
+/* { dg-final { scan-tree-dump-times "if " 0 "forwprop2" } } */
+
+/* By optimize there should be no min/max nor if  */
+/* { dg-final { scan-tree-dump-times "MAX_EXPR" 0 "optimized" } } */
+/* { dg-final { scan-tree-dump-times "MIN_EXPR" 0 "optimized" } } */
+/* { dg-final { scan-tree-dump-times "if " 0 "optimized" } } */
diff --git a/gcc/testsuite/gcc.dg/tree-ssa/minmax-20.c b/gcc/testsuite/gcc.dg/tree-ssa/minmax-20.c
new file mode 100644
index 0000000..ab64033
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/tree-ssa/minmax-20.c
@@ -0,0 +1,27 @@
+/* PR tree-optimization/109424 */
+/* { dg-do compile } */
+/* Need -O2 for early non-zero */
+/* { dg-options "-O2 -fdump-tree-forwprop1-raw" } */
+
+#define bool _Bool
+int maxbool(bool ab, bool bb)
+{
+  int a = ab;
+  int b = bb;
+  int c;
+  c = (a > b)?a : b;
+  return c;
+}
+int minbool(bool ab, bool bb)
+{
+  int a = ab;
+  int b = bb;
+  int c;
+  c = (a < b)?a : b;
+  return c;
+}
+
+/* { dg-final { scan-tree-dump-not "max_expr, " "forwprop1"} } */
+/* { dg-final { scan-tree-dump-not "min_expr, " "forwprop1"} } */
+/* { dg-final { scan-tree-dump-times "bit_and_expr, " 1 "forwprop1"} } */
+/* { dg-final { scan-tree-dump-times "bit_ior_expr, " 1 "forwprop1"} } */
diff --git a/gcc/testsuite/gcc.dg/tree-ssa/minmax-21.c b/gcc/testsuite/gcc.dg/tree-ssa/minmax-21.c
new file mode 100644
index 0000000..5f2b8af
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/tree-ssa/minmax-21.c
@@ -0,0 +1,28 @@
+/* PR tree-optimization/109424 */
+/* { dg-do compile } */
+/* Need -O2 for early non-zero bits */
+/* { dg-options "-O2 -fdump-tree-forwprop1-raw -fdump-tree-optimized-raw" } */
+
+
+int maxbool(int ab, int bb)
+{
+  int a = ab & 1;
+  int b = bb & 1;
+  int c;
+  c = (a > b)?a : b;
+  return c;
+}
+int minbool(int ab, int bb)
+{
+  int a = ab & 1;
+  int b = bb & 1;
+  int c;
+  c = (a < b)?a : b;
+  return c;
+}
+
+/* { dg-final { scan-tree-dump-not "max_expr, " "forwprop1"} } */
+/* { dg-final { scan-tree-dump-not "min_expr, " "forwprop1"} } */
+/* There should only be 3 total bit_and_expr, one &1 for each function and one & for minbool. */
+/* { dg-final { scan-tree-dump-times "bit_and_expr, " 3 "optimized"} } */
+/* { dg-final { scan-tree-dump-times "bit_ior_expr, " 1 "optimized"} } */