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re PR rtl-optimization/49720 (Infinite recursion compiling gold binary_test.cc testcase)

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2011-10-28  Chung-Lin Tang  <cltang@codesourcery.com>

	PR rtl-optimization/49720
	* simplify-rtx.c (simplify_relational_operation_1): Detect
	infinite recursion condition in "(eq/ne (plus x cst1) cst2)
	simplifies to (eq/ne x (cst2 - cst1))" case.

	testsuite/
	* g++.dg/torture/pr49720.C: New test.

From-SVN: r180604
This commit is contained in:
Chung-Lin Tang 2011-10-28 06:35:31 +00:00 • committed by Chung-Lin Tang
parent 2df19a351f
commit d303c992f6
4 changed files with 33 additions and 3 deletions
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7
gcc/ChangeLog
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@ -1,3 +1,10 @@
2011-10-28 Chung-Lin Tang <cltang@codesourcery.com>
PR rtl-optimization/49720
* simplify-rtx.c (simplify_relational_operation_1): Detect
infinite recursion condition in "(eq/ne (plus x cst1) cst2)
simplifies to (eq/ne x (cst2 - cst1))" case.
2011-10-27 David S. Miller <davem@davemloft.net>
* config/sparc/sparc.md (snedi_special): Only match when not VIS3.

16
gcc/simplify-rtx.c
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@ -4352,10 +4352,20 @@ simplify_relational_operation_1 (enum rtx_code code, enum machine_mode mode,
{
rtx x = XEXP (op0, 0);
rtx c = XEXP (op0, 1);
enum rtx_code invcode = op0code == PLUS ? MINUS : PLUS;
rtx tem = simplify_gen_binary (invcode, cmp_mode, op1, c);
c = simplify_gen_binary (op0code == PLUS ? MINUS : PLUS,
cmp_mode, op1, c);
return simplify_gen_relational (code, mode, cmp_mode, x, c);
/* Detect an infinite recursive condition, where we oscillate at this
simplification case between:
A + B == C <---> C - B == A,
where A, B, and C are all constants with non-simplifiable expressions,
usually SYMBOL_REFs. */
if (GET_CODE (tem) == invcode
&& CONSTANT_P (x)
&& rtx_equal_p (c, XEXP (tem, 1)))
return NULL_RTX;
return simplify_gen_relational (code, mode, cmp_mode, x, tem);
}
/* (ne:SI (zero_extract:SI FOO (const_int 1) BAR) (const_int 0))) is

5
gcc/testsuite/ChangeLog
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@ -1,3 +1,8 @@
2011-10-28 Chung-Lin Tang <cltang@codesourcery.com>
PR rtl-optimization/49720
* g++.dg/torture/pr49720.C: New test.
2011-10-27 David S. Miller <davem@davemloft.net>
* gcc.target/sparc/setcc-3.c: New test.

8
gcc/testsuite/g++.dg/torture/pr49720.C Normal file
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@ -0,0 +1,8 @@
/* { dg-do compile } */
extern char t_start[], t_end[], t_size[];
bool foo (void)
{
long size = reinterpret_cast<long>(t_size);
return (size == t_end - t_start);
}