From: Kugan <kugan.vivekanandarajah@linaro.org>
To: "gcc-patches@gcc.gnu.org" <gcc-patches@gcc.gnu.org>
Cc: Richard Earnshaw <Richard.Earnshaw@arm.com>,
Ramana Radhakrishnan <ramrad01@arm.com>,
Kyrill Tkachov <kyrylo.tkachov@arm.com>
Subject: Incorrect code due to indirect tail call of varargs function with hard float ABI
Date: Mon, 16 Nov 2015 22:25:00 -0000 [thread overview]
Message-ID: <564A57BA.7050504@linaro.org> (raw)
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Following testcase fails on ARM (from
https://bugs.linaro.org/show_bug.cgi?id=1900).
__attribute__ ((noinline))
double direct(int x, ...)
{
return x*x;
}
__attribute__ ((noinline))
double broken(double (*indirect)(int x, ...), int v)
{
return indirect(v);
}
int main ()
{
double d1, d2;
int i = 2;
d1 = broken (direct, i);
if (d1 != i*i)
{
__builtin_abort ();
}
return 0;
}
Please note that we have a sibcall from "broken" to "indirect".
"direct" is variadic function so it is conforming to AAPCS base standard.
"broken" is a non-variadic function and will return the value in
floating point register for TARGET_HARD_FLOAT. Thus we should not be
doing sibcall here.
Attached patch fixes this. Bootstrap and regression testing is ongoing.
Is this OK if no issues with the testing?
Thanks,
Kugan
gcc/ChangeLog:
2015-11-17 Kugan Vivekanandarajah <kuganv@linaro.org>
* config/arm/arm.c (arm_function_ok_for_sibcall): Disable sibcall to
indirect function when TARGET_HARD_FLOAT.
gcc/testsuite/ChangeLog:
2015-11-17 Kugan Vivekanandarajah <kuganv@linaro.org>
* gcc.target/arm/variadic_sibcall.c: New test.
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diff --git a/gcc/config/arm/arm.c b/gcc/config/arm/arm.c
index a379121..8b560bc 100644
--- a/gcc/config/arm/arm.c
+++ b/gcc/config/arm/arm.c
@@ -6681,6 +6681,12 @@ arm_function_ok_for_sibcall (tree decl, tree exp)
register. */
rtx a, b;
+ /* When it is an indirect call (i.e, decl == NULL), it could be
+ returning its result in a VFP or could be a variadic function.
+ Thus return false. */
+ if (!decl && TARGET_HARD_FLOAT)
+ return false;
+
a = arm_function_value (TREE_TYPE (exp), decl, false);
b = arm_function_value (TREE_TYPE (DECL_RESULT (cfun->decl)),
cfun->decl, false);
diff --git a/gcc/testsuite/gcc.target/arm/variadic_sibcall.c b/gcc/testsuite/gcc.target/arm/variadic_sibcall.c
index e69de29..86f07fe 100644
--- a/gcc/testsuite/gcc.target/arm/variadic_sibcall.c
+++ b/gcc/testsuite/gcc.target/arm/variadic_sibcall.c
@@ -0,0 +1,27 @@
+/* { dg-do run } */
+/* { dg-options "-O2" } */
+
+__attribute__ ((noinline))
+double direct(int x, ...)
+{
+ return x*x;
+}
+
+__attribute__ ((noinline))
+double broken(double (*indirect)(int x, ...), int v)
+{
+ return indirect(v);
+}
+
+int main ()
+{
+ double d1, d2;
+ int i = 2;
+ d1 = broken (direct, i);
+ if (d1 != i*i)
+ {
+ __builtin_abort ();
+ }
+ return 0;
+}
+
next reply other threads:[~2015-11-16 22:25 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-11-16 22:25 Kugan [this message]
2015-11-17 1:00 ` Charles Baylis
2015-11-17 1:27 ` Kugan
2015-11-17 2:38 ` Kugan
2015-11-17 10:05 ` Ramana Radhakrishnan
2015-11-17 19:56 ` Kugan
2015-11-18 0:32 ` Kugan
2015-11-18 9:19 ` Ramana Radhakrishnan
2015-12-01 23:00 ` Kugan
2016-01-25 21:54 ` Kugan
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