From: Andrew Pinski <apin...@marvell.com>
The problem here is that when we mark the ssa name that was referenced in the
now removed
dead store (to a write only static variable), the inline-asm would also be
removed
even though it was defining another ssa name. This fixes the problem by checking
to make sure that the statement was only defining one ssa name.
OK? Bootstrapped and tested on x86_64 with no regressions.
PR tree-optimization/106087
gcc/ChangeLog:
* tree-ssa-dce.cc (simple_dce_from_worklist): Check
to make sure the statement is only defining one operand.
gcc/testsuite/ChangeLog:
* gcc.c-torture/compile/inline-asm-1.c: New test.
---
gcc/testsuite/gcc.c-torture/compile/inline-asm-1.c | 14 ++++++++++++++
gcc/tree-ssa-dce.cc | 5 +++++
2 files changed, 19 insertions(+)
create mode 100644 gcc/testsuite/gcc.c-torture/compile/inline-asm-1.c
diff --git a/gcc/testsuite/gcc.c-torture/compile/inline-asm-1.c
b/gcc/testsuite/gcc.c-torture/compile/inline-asm-1.c
new file mode 100644
index 00000000000..0044cb761b6
--- /dev/null
+++ b/gcc/testsuite/gcc.c-torture/compile/inline-asm-1.c
@@ -0,0 +1,14 @@
+/* PR tree-opt/106087,
+ simple_dce_from_worklist would delete the
+ inline-asm when it was still being referenced
+ by the other ssa name. */
+
+static int t;
+
+int f(void)
+{
+ int tt, tt1;
+ asm("":"=r"(tt), "=r"(tt1));
+ t = tt1;
+ return tt;
+}
diff --git a/gcc/tree-ssa-dce.cc b/gcc/tree-ssa-dce.cc
index bc533582673..602cdb30ceb 100644
--- a/gcc/tree-ssa-dce.cc
+++ b/gcc/tree-ssa-dce.cc
@@ -2061,6 +2061,11 @@ simple_dce_from_worklist (bitmap worklist)
if (gimple_has_side_effects (t))
continue;
+ /* The defining statement needs to be defining one this name. */
+ if (!is_a<gphi *>(t)
+ && !single_ssa_def_operand (t, SSA_OP_DEF))
+ continue;
+
/* Don't remove statements that are needed for non-call
eh to work. */
if (stmt_unremovable_because_of_non_call_eh_p (cfun, t))
--
2.17.1
