Because of C's integer promotion, in code like 'a == 0',
the operand 'a' must be promoted to int. So, if 'a' is
of type 'bool', it results in following linearization:
zext.32 %t <- (1) %a
setne.32 %r <- %t, $0
While this promotion is required by the standard at C level,
here, from an operational PoV, the zero-extension is unneeded
since the result will be the same without it.
Change this by simplifying away such zero-extensions.
Signed-off-by: Luc Van Oostenryck <luc.vanoostenryck@xxxxxxxxx>
---
simplify.c | 15 ++++++++++++++-
validation/optim/bool-int-bool.c | 12 ++++++++++++
validation/optim/bool-simplify2.c | 5 ++---
3 files changed, 28 insertions(+), 4 deletions(-)
create mode 100644 validation/optim/bool-int-bool.c
diff --git a/simplify.c b/simplify.c
index c88ea5c33..9f0d13b55 100644
--- a/simplify.c
+++ b/simplify.c
@@ -612,9 +612,22 @@ static int simplify_seteq_setne(struct instruction *insn, long long value)
remove_usage(old, &insn->src1);
return REPEAT_CSE;
+ case OP_ZEXT:
+ if (def->orig_type->bit_size == 1) {
+ // Convert:
+ // zext.n %s <- (1) %a
+ // setne.n %r <- %s, $0
+ // into:
+ // setne.n %s <- %a, $0
+ // and same for setne/eq ... 0/1
+ return replace_pseudo(insn, &insn->src1, def->src1);
+ }
+ break;
+
default:
- return 0;
+ break;
}
+ return 0;
}
static int simplify_constant_rightside(struct instruction *insn)
diff --git a/validation/optim/bool-int-bool.c b/validation/optim/bool-int-bool.c
new file mode 100644
index 000000000..de34a68bb
--- /dev/null
+++ b/validation/optim/bool-int-bool.c
@@ -0,0 +1,12 @@
+_Bool beq0(_Bool a) { return (a == 0); }
+_Bool beq1(_Bool a) { return (a == 1); }
+_Bool bne0(_Bool a) { return (a != 0); }
+_Bool bne1(_Bool a) { return (a != 1); }
+
+/*
+ * check-name: bool - int - bool constants
+ * check-command: test-linearize -Wno-decl $file
+ *
+ * check-output-ignore
+ * check-output-excludes: cast\\.
+ */
diff --git a/validation/optim/bool-simplify2.c b/validation/optim/bool-simplify2.c
index 7e7548fc5..72fc2f2ea 100644
--- a/validation/optim/bool-simplify2.c
+++ b/validation/optim/bool-simplify2.c
@@ -8,7 +8,7 @@ static int foo(int a, int b, int c)
* check-command: test-linearize $file
*
* check-output-pattern(4): setne\\.
- * check-output-pattern(2): zext\\.
+ * check-output-pattern(1): zext\\.
*
* check-output-start
foo:
@@ -17,8 +17,7 @@ foo:
setne.1 %r2 <- %arg1, $0
setne.1 %r4 <- %arg2, $0
or-bool.1 %r5 <- %r2, %r4
- zext.32 %r6 <- (1) %r5
- setne.1 %r7 <- %r6, $0
+ setne.1 %r7 <- %r5, $0
setne.1 %r9 <- %arg3, $0
or-bool.1 %r10 <- %r7, %r9
zext.32 %r11 <- (1) %r10
--
2.18.0
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