Hi!
As mentioned in the PR, the following testcase is miscompiled for similar
reasons as the already fixed PR78791 - we use SLOT_TEMP slots in various
places during expansion and during expansion we can guarantee that the
lifetime of those temporary slot doesn't overlap. But the following
splitter uses SLOT_TEMP too and in between expansion and split1 there is
a possibility that something extends the lifetime of SLOT_TEMP created
slots across an instruction that will be split by this splitter.
The following patch fixes it by using a new temp slot kind to make sure
it doesn't reuse a SLOT_TEMP that could be live across the instruction.
Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?
2022-02-24 Jakub Jelinek <ja...@redhat.com>
PR target/104674
* config/i386/i386.h (enum ix86_stack_slot): Add SLOT_FLOATxFDI_387.
* config/i386/i386.md (splitter to floatdi<mode>2_i387_with_xmm): Use
SLOT_FLOATxFDI_387 rather than SLOT_TEMP.
* gcc.target/i386/pr104674.c: New test.
--- gcc/config/i386/i386.h.jj 2022-01-18 11:58:59.118988685 +0100
+++ gcc/config/i386/i386.h 2022-02-24 13:47:02.809289843 +0100
@@ -2414,6 +2414,7 @@ enum ix86_stack_slot
SLOT_CW_FLOOR,
SLOT_CW_CEIL,
SLOT_STV_TEMP,
+ SLOT_FLOATxFDI_387,
MAX_386_STACK_LOCALS
};
--- gcc/config/i386/i386.md.jj 2022-02-12 11:17:35.149999347 +0100
+++ gcc/config/i386/i386.md 2022-02-24 13:35:57.832561968 +0100
@@ -5412,9 +5412,8 @@ (define_split
&& can_create_pseudo_p ()"
[(const_int 0)]
{
- emit_insn (gen_floatdi<mode>2_i387_with_xmm
- (operands[0], operands[1],
- assign_386_stack_local (DImode, SLOT_TEMP)));
+ rtx s = assign_386_stack_local (DImode, SLOT_FLOATxFDI_387);
+ emit_insn (gen_floatdi<mode>2_i387_with_xmm (operands[0], operands[1], s));
DONE;
})
--- gcc/testsuite/gcc.target/i386/pr104674.c.jj 2022-02-24 13:45:31.630561330
+0100
+++ gcc/testsuite/gcc.target/i386/pr104674.c 2022-02-24 13:45:21.278705687
+0100
@@ -0,0 +1,31 @@
+/* PR target/104674 */
+/* { dg-do run { target sse2_runtime } } */
+/* { dg-options "-O2 -msse2 -mfpmath=sse" } */
+
+__attribute__((noipa)) double
+bar (double x, double y)
+{
+ return x + y;
+}
+
+__attribute__((noipa)) double
+foo (long long x)
+{
+ long long a = x / 10000000;
+ int b = x % 10000000;
+ double s = (double) a;
+ double n = (double) b / 1e7;
+ double t = s + n;
+ if (t == s + 1.0)
+ t = bar (t, s);
+ return t;
+}
+
+int
+main ()
+{
+ long long n = 888888;
+ n = n * 10000000;
+ if (foo (n) != 888888.0)
+ __builtin_abort ();
+}
Jakub
