diff options
| author | Richard Kenner <kenner@gcc.gnu.org> | 1997-07-13 15:11:06 -0400 |
|---|---|---|
| committer | Richard Kenner <kenner@gcc.gnu.org> | 1997-07-13 15:11:06 -0400 |
| commit | 79d06d29adcb59b8e0e1a36f3d3ccfaff10bee47 (patch) | |
| tree | 9d5b3e6fcc8578c427f5a7c73f6e2696027adb40 | |
| parent | a23ea59844cf672a4bc1a57ee0f47f9c75fe7a0c (diff) | |
| download | gcc-79d06d29adcb59b8e0e1a36f3d3ccfaff10bee47.zip gcc-79d06d29adcb59b8e0e1a36f3d3ccfaff10bee47.tar.gz gcc-79d06d29adcb59b8e0e1a36f3d3ccfaff10bee47.tar.bz2 | |
(stupid_mark_refs): If setting reg set only in this insn and not
referenced, make REG_UNUSED note.
From-SVN: r14416
| -rw-r--r-- | gcc/stupid.c | 15 |
1 files changed, 14 insertions, 1 deletions
diff --git a/gcc/stupid.c b/gcc/stupid.c index 396799e..9a18e55 100644 --- a/gcc/stupid.c +++ b/gcc/stupid.c @@ -1,5 +1,5 @@ /* Dummy data flow analysis for GNU compiler in nonoptimizing mode. - Copyright (C) 1987, 1991, 1994, 1995, 1996, 1997 Free Software Foundation, Inc. + Copyright (C) 1987, 91, 94, 95, 96, 1997 Free Software Foundation, Inc. This file is part of GNU CC. @@ -514,6 +514,19 @@ stupid_mark_refs (x, insn) if (last_setjmp_suid < reg_where_dead[regno]) regs_crosses_setjmp[regno] = 1; + + /* If this register is only used in this insn and is only + set, mark it unused. We have to do this even when not + optimizing so that MD patterns which count on this + behavior (e.g., it not causing an output reload on + an insn setting CC) will operate correctly. */ + if (GET_CODE (SET_DEST (x)) == REG + &&& REGNO_FIRST_UID (regno) == INSN_UID (insn) + && REGNO_LAST_UID (regno) == INSN_UID (insn) + && (code == CLOBBER || ! reg_mentioned_p (SET_DEST (x), + SET_SRC (x)))) + REG_NOTES (insn) = gen_rtx (EXPR_LIST, REG_UNUSED, + SET_DEST (x), REG_NOTES (insn)); } } |