A few testcases for separate shrink-wrapping: test whether it works in a
trivial case; whether it creates more than one prologue where that is
useful; whether it puts prologues inside a loop if that is cheaper.
2016-10-03 Segher Boessenkool <seg...@kernel.crashing.org>
gcc/testsuite/
* gcc.target/powerpc/shrink-wrap-separate-0.c: New testcase.
* gcc.target/powerpc/shrink-wrap-separate-1.c: New testcase.
* gcc.target/powerpc/shrink-wrap-separate-2.c: New testcase.
---
.../gcc.target/powerpc/shrink-wrap-separate-0.c | 22 ++++++++++++++++++
.../gcc.target/powerpc/shrink-wrap-separate-1.c | 18 +++++++++++++++
.../gcc.target/powerpc/shrink-wrap-separate-2.c | 26 ++++++++++++++++++++++
3 files changed, 66 insertions(+)
create mode 100644 gcc/testsuite/gcc.target/powerpc/shrink-wrap-separate-0.c
create mode 100644 gcc/testsuite/gcc.target/powerpc/shrink-wrap-separate-1.c
create mode 100644 gcc/testsuite/gcc.target/powerpc/shrink-wrap-separate-2.c
diff --git a/gcc/testsuite/gcc.target/powerpc/shrink-wrap-separate-0.c
b/gcc/testsuite/gcc.target/powerpc/shrink-wrap-separate-0.c
new file mode 100644
index 0000000..dea0611
--- /dev/null
+++ b/gcc/testsuite/gcc.target/powerpc/shrink-wrap-separate-0.c
@@ -0,0 +1,22 @@
+/* { dg-do compile { target powerpc*-*-* } } */
+/* { dg-options "-O2" } */
+/* { dg-final { scan-assembler {#before\M.*\mmflr\M} } } */
+
+/* This tests if shrink-wrapping for separate components works.
+
+ r20 (a callee-saved register) is forced live at the start, so that we
+ get it saved in a prologue at the start of the function.
+ The link register only needs to be saved if x is non-zero; without
+ separate shrink-wrapping it would however be saved in the one prologue.
+ The test tests if the mflr insn ends up behind the prologue. */
+
+void g(void);
+
+void f(int x)
+{
+ register int r20 asm("20") = x;
+ asm("#before" : : "r"(r20));
+ if (x)
+ g();
+ asm(""); // no tailcall of g
+}
diff --git a/gcc/testsuite/gcc.target/powerpc/shrink-wrap-separate-1.c
b/gcc/testsuite/gcc.target/powerpc/shrink-wrap-separate-1.c
new file mode 100644
index 0000000..735b606
--- /dev/null
+++ b/gcc/testsuite/gcc.target/powerpc/shrink-wrap-separate-1.c
@@ -0,0 +1,18 @@
+/* { dg-do compile { target powerpc*-*-* } } */
+/* { dg-options "-O2" } */
+/* { dg-final { scan-assembler {\mmflr\M.*\mbl\M.*\mmflr\M.*\mbl\M} } } */
+
+/* This tests if shrink-wrapping for separate components creates more
+ than one prologue when that is useful. In this case, it saves the
+ link register before both the call to g and the call to h. */
+
+void g(void) __attribute__((noreturn));
+void h(void) __attribute__((noreturn));
+
+void f(int x)
+{
+ if (x == 42)
+ g();
+ if (x == 31)
+ h();
+}
diff --git a/gcc/testsuite/gcc.target/powerpc/shrink-wrap-separate-2.c
b/gcc/testsuite/gcc.target/powerpc/shrink-wrap-separate-2.c
new file mode 100644
index 0000000..b22564a
--- /dev/null
+++ b/gcc/testsuite/gcc.target/powerpc/shrink-wrap-separate-2.c
@@ -0,0 +1,26 @@
+/* { dg-do compile { target powerpc*-*-* } } */
+/* { dg-options "-O2" } */
+/* { dg-final { scan-assembler {\mmflr\M.*\mbl\M.*\mmflr\M.*\mbl\M} } } */
+
+/* This tests if shrink-wrapping for separate components puts a prologue
+ inside a loop when that is useful. In this case, it saves the link
+ register before each call: both calls happen with probability .10,
+ so saving the link register happens with .80 per execution of f on
+ average, which is smaller than 1 which you would get if you saved
+ it outside the loop. */
+
+int *a;
+void g(void);
+
+void f(int x)
+{
+ int j;
+ for (j = 0; j < 4; j++) {
+ if (__builtin_expect(a[j], 0))
+ g();
+ asm("#" : : : "memory");
+ if (__builtin_expect(a[j], 0))
+ g();
+ a[j]++;
+ }
+}
--
1.9.3
