The mulu.l insn sets the CC according to the 64-bit result, but we are
only using the high part, so the Z flag cannot be used. The other flags
would still be valid, but we have no cc_status flag for that case.
* config/m68k/m68k.md (umulsi3_highpart+1, const_umulsi3_highpart)
(smulsi3_highpart+1, const_smulsi3_highpart): Add CC_STATUS_INIT.
testsuite/:
* gcc.target/m68k/mulsi_highpart.c: New test.
diff --git a/gcc/config/m68k/m68k.md b/gcc/config/m68k/m68k.md
index f8a674d7d9..74c366fc63 100644
--- a/gcc/config/m68k/m68k.md
+++ b/gcc/config/m68k/m68k.md
@@ -3240,7 +3240,10 @@
(const_int 32))))
(clobber (match_operand:SI 1 "register_operand" "=d"))]
"TARGET_68020 && !TUNE_68060 && !TARGET_COLDFIRE"
- "mulu%.l %3,%0:%1")
+{
+ CC_STATUS_INIT;
+ return "mulu%.l %3,%0:%1";
+})
(define_insn "const_umulsi3_highpart"
[(set (match_operand:SI 0 "register_operand" "=d")
@@ -3251,7 +3254,10 @@
(const_int 32))))
(clobber (match_operand:SI 1 "register_operand" "=d"))]
"TARGET_68020 && !TUNE_68060 && !TARGET_COLDFIRE"
- "mulu%.l %3,%0:%1")
+{
+ CC_STATUS_INIT;
+ return "mulu%.l %3,%0:%1";
+})
(define_expand "smulsi3_highpart"
[(parallel
@@ -3283,7 +3289,10 @@
(const_int 32))))
(clobber (match_operand:SI 1 "register_operand" "=d"))]
"TARGET_68020 && !TUNE_68060 && !TARGET_COLDFIRE"
- "muls%.l %3,%0:%1")
+{
+ CC_STATUS_INIT;
+ return "muls%.l %3,%0:%1";
+})
(define_insn "const_smulsi3_highpart"
[(set (match_operand:SI 0 "register_operand" "=d")
@@ -3294,7 +3303,10 @@
(const_int 32))))
(clobber (match_operand:SI 1 "register_operand" "=d"))]
"TARGET_68020 && !TUNE_68060 && !TARGET_COLDFIRE"
- "muls%.l %3,%0:%1")
+{
+ CC_STATUS_INIT;
+ return "muls%.l %3,%0:%1";
+})
(define_expand "mul<mode>3"
[(set (match_operand:FP 0 "nonimmediate_operand" "")
diff --git a/gcc/testsuite/gcc.target/m68k/mulsi_highpart.c
b/gcc/testsuite/gcc.target/m68k/mulsi_highpart.c
new file mode 100644
index 0000000000..f17586ee52
--- /dev/null
+++ b/gcc/testsuite/gcc.target/m68k/mulsi_highpart.c
@@ -0,0 +1,8 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -m68020" } */
+/* Don't optimize away a compare after [us]mulsi_highpart. */
+/* { dg-final { scan-assembler {tst\.?l} } } */
+int cmp (unsigned int a, unsigned int b)
+{
+ return (a > 0xffffffff / b);
+}
--
2.18.0
--
Andreas Schwab, sch...@linux-m68k.org
GPG Key fingerprint = 7578 EB47 D4E5 4D69 2510 2552 DF73 E780 A9DA AEC1
"And now for something completely different."
