74 lines
2.6 KiB
Diff
74 lines
2.6 KiB
Diff
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2013-02-11 Jakub Jelinek <jakub@redhat.com>
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Steven Bosscher <steven@gcc.gnu.org>
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PR rtl-optimization/56151
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* optabs.c (add_equal_note): Don't return 0 if target is a MEM,
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equal to op0 or op1, and last_insn pattern is CODE operation
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with MEM dest and one of the operands matches that MEM.
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* gcc.target/i386/pr56151.c: New test.
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--- gcc/optabs.c.jj 2013-01-16 08:30:10.000000000 +0100
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+++ gcc/optabs.c 2013-02-11 15:28:16.543839881 +0100
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@@ -190,17 +190,34 @@ add_equal_note (rtx insns, rtx target, e
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if (GET_CODE (target) == ZERO_EXTRACT)
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return 1;
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- /* If TARGET is in OP0 or OP1, punt. We'd end up with a note referencing
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- a value changing in the insn, so the note would be invalid for CSE. */
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- if (reg_overlap_mentioned_p (target, op0)
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- || (op1 && reg_overlap_mentioned_p (target, op1)))
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- return 0;
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-
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for (last_insn = insns;
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NEXT_INSN (last_insn) != NULL_RTX;
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last_insn = NEXT_INSN (last_insn))
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;
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+ /* If TARGET is in OP0 or OP1, punt. We'd end up with a note referencing
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+ a value changing in the insn, so the note would be invalid for CSE. */
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+ if (reg_overlap_mentioned_p (target, op0)
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+ || (op1 && reg_overlap_mentioned_p (target, op1)))
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+ {
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+ if (MEM_P (target)
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+ && (rtx_equal_p (target, op0)
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+ || (op1 && rtx_equal_p (target, op1))))
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+ {
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+ /* For MEM target, with MEM = MEM op X, prefer no REG_EQUAL note
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+ over expanding it as temp = MEM op X, MEM = temp. See PR56151. */
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+ set = single_set (last_insn);
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+ if (set
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+ && GET_CODE (SET_SRC (set)) == code
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+ && MEM_P (SET_DEST (set))
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+ && (rtx_equal_p (SET_DEST (set), XEXP (SET_SRC (set), 0))
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+ || (op1 && rtx_equal_p (SET_DEST (set),
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+ XEXP (SET_SRC (set), 1)))))
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+ return 1;
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+ }
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+ return 0;
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+ }
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+
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set = single_set (last_insn);
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if (set == NULL_RTX)
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return 1;
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--- gcc/testsuite/gcc.target/i386/pr56151.c.jj 2013-02-11 16:20:51.459752951 +0100
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+++ gcc/testsuite/gcc.target/i386/pr56151.c 2013-02-11 16:23:10.590964710 +0100
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@@ -0,0 +1,17 @@
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+/* PR rtl-optimization/56151 */
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+/* { dg-do compile } */
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+/* { dg-options "-O2" } */
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+
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+int vara, varb;
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+
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+void
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+foo (int i, int j)
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+{
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+ vara = varb | vara;
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+}
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+
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+/* Verify the above is compiled into movl varb, %reg; orl %reg, vara instead
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+ of longer movl vara, %reg; orl varb, %reg; movl %reg, vara. */
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+/* { dg-final { scan-assembler-not "mov\[^\n\r]*vara" { target nonpic } } } */
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+/* { dg-final { scan-assembler-times "mov\[^\n\r]*varb" 1 { target nonpic } } } */
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+/* { dg-final { scan-assembler-times "or\[^\n\r]*vara" 1 { target nonpic } } } */
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