Merge branch 'optim-sel' into next

* simplify SEL(SEL(...), ...)
* simplify SEL(x == y, x, y) and friends
* simplify SEL(x, x, x) and SEL(x, 0, x)

9 files changed, 122 insertions, 21 deletions

diff --git a/simplify.c b/simplify.c
index f2aaa52d..6713e8af 100644
--- a/simplify.c
+++ b/simplify.c
@@ -1748,18 +1748,17 @@ static int simplify_cast(struct instruction *insn)
 static int simplify_select(struct instruction *insn)
 {
 	pseudo_t cond, src1, src2;
+	struct instruction *def;
 
 	cond = insn->src1;
 	src1 = insn->src2;
 	src2 = insn->src3;
-	if (constant(cond) || src1 == src2) {
-		pseudo_t *kill, take;
-		kill_use(&insn->src1);
-		take = cond->value ? src1 : src2;
-		kill = cond->value ? &insn->src3 : &insn->src2;
-		kill_use(kill);
-		return replace_with_pseudo(insn, take);
-	}
+
+	if (constant(cond))
+		return replace_with_pseudo(insn, cond->value ? src1 : src2);
+	if (src1 == src2)
+		return replace_with_pseudo(insn, src1);
+
 	if (constant(src1) && constant(src2)) {
 		long long val1 = src1->value;
 		long long val2 = src2->value;
@@ -1777,10 +1776,46 @@ static int simplify_select(struct instruction *insn)
 			return REPEAT_CSE;
 		}
 	}
-	if (cond == src2 && is_zero(src1)) {
-		kill_use(&insn->src1);
-		kill_use(&insn->src3);
-		return replace_with_value(insn, 0);
+	if (cond == src2 && is_zero(src1))			// SEL(x, 0, x) --> 0
+		return replace_with_pseudo(insn, src1);
+	if (cond == src1 && is_zero(src2))			// SEL(x, x, 0) --> x
+		return replace_with_pseudo(insn, cond);
+
+	switch (DEF_OPCODE(def, cond)) {
+	case OP_SET_EQ:
+		if (src1 == def->src1 && src2 == def->src2)
+			return replace_with_pseudo(insn, src2); // SEL(x==y,x,y) --> y
+		if (src2 == def->src1 && src1 == def->src2)
+			return replace_with_pseudo(insn, src2); // SEL(y==x,x,y) --> y
+		break;
+	case OP_SET_NE:
+		if (src1 == def->src1 && src2 == def->src2)
+			return replace_with_pseudo(insn, src1); // SEL(x!=y,x,y) --> x
+		if (src2 == def->src1 && src1 == def->src2)
+			return replace_with_pseudo(insn, src1); // SEL(y!=x,x,y) --> x
+		break;
+	case OP_SEL:
+		if (constant(def->src2) && constant(def->src3)) {
+			// Is the def of the conditional another select?
+			// And if that one results in a "zero or not", use the
+			// original conditional instead.
+			//	SEL(SEL(x, C, 0), y, z) --> SEL(x, y, z)
+			//	SEL(SEL(x, C, 0), C, 0) --> SEL(x, C, 0) == cond
+			//	SEL(SEL(x, 0, C), y, z) --> SEL(x, z, y)
+			//	SEL(SEL(x, C1, C2), y, z) --> y
+			if (!def->src3->value) {
+				if ((src1 == def->src2) && (src2 == def->src3))
+					return replace_with_pseudo(insn, cond);
+				return replace_pseudo(insn, &insn->cond, def->cond);
+			}
+			if (!def->src2->value) {
+				switch_pseudo(insn, &insn->src2, insn, &insn->src3);
+				return replace_pseudo(insn, &insn->cond, def->cond);
+			}
+			// both values must be non-zero
+			return replace_with_pseudo(insn, src1);
+		}
+		break;
 	}
 	return 0;
 }
diff --git a/validation/optim/call-inlined.c b/validation/optim/call-inlined.c
index f21b3294..7f5f4e89 100644
--- a/validation/optim/call-inlined.c
+++ b/validation/optim/call-inlined.c
@@ -18,13 +18,6 @@ int foo(int a, int b, int p)
  * check-name: call-inlined
  * check-command: test-linearize -Wno-decl $file
  *
- * check-output-start
-foo:
-.L0:
-	<entry-point>
-	select.32   %r10 <- %arg3, %arg3, $0
-	ret.32      %r10
-
-
- * check-output-end
+ * check-output-ignore
+ * check-output-returns: %arg3
  */
diff --git a/validation/optim/eqne-select.c b/validation/optim/eqne-select.c
new file mode 100644
index 00000000..9dfd88b5
--- /dev/null
+++ b/validation/optim/eqne-select.c
@@ -0,0 +1,12 @@
+int sel_eq01(int a, int b) { return ((a == b) ? a : b) == b; }
+int sel_eq10(int a, int b) { return ((a == b) ? b : a) == a; }
+int sel_ne01(int a, int b) { return ((a != b) ? a : b) == a; }
+int sel_ne10(int a, int b) { return ((a != b) ? b : a) == b; }
+
+/*
+ * check-name: eqne-select
+ * check-command: test-linearize -Wno-decl $file
+ *
+ * check-output-ignore
+ * check-output-returns: 1
+ */
diff --git a/validation/optim/select-constant-cond.c b/validation/optim/select-constant-cond.c
new file mode 100644
index 00000000..a9337e2c
--- /dev/null
+++ b/validation/optim/select-constant-cond.c
@@ -0,0 +1,10 @@
+int t(int p, int a, int b) { return ((p == p) ? a : b) == a; }
+int f(int p, int a, int b) { return ((p != p) ? a : b) == b; }
+
+/*
+ * check-name: select-constant-cond
+ * check-command: test-linearize -Wno-decl $file
+ *
+ * check-output-ignore
+ * check-output-returns: 1
+ */
diff --git a/validation/optim/select-same-args.c b/validation/optim/select-same-args.c
new file mode 100644
index 00000000..403af471
--- /dev/null
+++ b/validation/optim/select-same-args.c
@@ -0,0 +1,9 @@
+int foo(int p, int a) { return (p ? a : a) == a; }
+
+/*
+ * check-name: select-same-args
+ * check-command: test-linearize -Wno-decl $file
+ *
+ * check-output-ignore
+ * check-output-returns: 1
+ */
diff --git a/validation/optim/select-select-true-false0.c b/validation/optim/select-select-true-false0.c
new file mode 100644
index 00000000..4066c2da
--- /dev/null
+++ b/validation/optim/select-select-true-false0.c
@@ -0,0 +1,10 @@
+int fw(int p, int a, int b) { return ((p ? 42 : 0) ? a : b) == ( p ? a : b); }
+int bw(int p, int a, int b) { return ((p ? 0 : 42) ? a : b) == ( p ? b : a); }
+
+/*
+ * check-name: select-select-true-false0
+ * check-command: test-linearize -Wno-decl $file
+ *
+ * check-output-ignore
+ * check-output-returns: 1
+ */
diff --git a/validation/optim/select-select-true-false1.c b/validation/optim/select-select-true-false1.c
new file mode 100644
index 00000000..32c0364d
--- /dev/null
+++ b/validation/optim/select-select-true-false1.c
@@ -0,0 +1,13 @@
+int foo(int p)
+{
+	int t = (p ? 42 : 0);
+	return (t ? 42 : 0) == ( p ? 42 : 0);
+}
+
+/*
+ * check-name: select-select-true-false1
+ * check-command: test-linearize -Wno-decl $file
+ *
+ * check-output-ignore
+ * check-output-returns: 1
+ */
diff --git a/validation/optim/select-select-true-true.c b/validation/optim/select-select-true-true.c
new file mode 100644
index 00000000..c0c26fdd
--- /dev/null
+++ b/validation/optim/select-select-true-true.c
@@ -0,0 +1,9 @@
+int foo(int p, int a, int b) { return ((p ? 42 : 43) ? a : b) == a ; }
+
+/*
+ * check-name: select-select-true-true
+ * check-command: test-linearize -Wno-decl $file
+ *
+ * check-output-ignore
+ * check-output-returns: 1
+ */
diff --git a/validation/optim/select-self-zero.c b/validation/optim/select-self-zero.c
new file mode 100644
index 00000000..73b3a3dc
--- /dev/null
+++ b/validation/optim/select-self-zero.c
@@ -0,0 +1,10 @@
+int sel_self0x(int x) { return (x ? 0 : x) == 0; }
+int sel_selfx0(int x) { return (x ? x : 0) == x; }
+
+/*
+ * check-name: select-self-zero
+ * check-command: test-linearize -Wno-decl $file
+ *
+ * check-output-ignore
+ * check-output-returns: 1
+ */