man gcc:
Warn if in a loop with constant number of iterations the compiler
detects undefined behavior in some statement during one or more of
the iterations.
Refactored the code a bit to avoid the GCC warning, in an objectionable
way,
hw/misc/milkymist-pfpu.c: In function ‘pfpu_write’:
hw/misc/milkymist-pfpu.c:365:20: error: loop exit may only be reached after
undefined behavior [-Werror=aggressive-loop-optimizations]
if (i++ >= MICROCODE_WORDS) {
^
hw/misc/milkymist-pfpu.c:167:14: note: possible undefined statement is here
uint32_t insn = s->microcode[pc];
^
Signed-off-by: Radim Krčmář <rkrc...@redhat.com>
---
hw/misc/milkymist-pfpu.c | 18 ++++++++----------
1 file changed, 8 insertions(+), 10 deletions(-)
diff --git a/hw/misc/milkymist-pfpu.c b/hw/misc/milkymist-pfpu.c
index 609f33f9cd14..133f5b8c5153 100644
--- a/hw/misc/milkymist-pfpu.c
+++ b/hw/misc/milkymist-pfpu.c
@@ -164,6 +164,13 @@ output_queue_advance(MilkymistPFPUState *s)
static int pfpu_decode_insn(MilkymistPFPUState *s)
{
uint32_t pc = s->regs[R_PC];
+
+ if (pc > MICROCODE_WORDS) {
+ error_report("milkymist_pfpu: too many instructions "
+ "executed in microcode. No VECTOUT?");
+ return 0;
+ }
+
uint32_t insn = s->microcode[pc];
uint32_t reg_a = (insn >> 18) & 0x7f;
uint32_t reg_b = (insn >> 11) & 0x7f;
@@ -348,7 +355,6 @@ static int pfpu_decode_insn(MilkymistPFPUState *s)
static void pfpu_start(MilkymistPFPUState *s)
{
int x, y;
- int i;
for (y = 0; y <= s->regs[R_VMESHLAST]; y++) {
for (x = 0; x <= s->regs[R_HMESHLAST]; x++) {
@@ -359,15 +365,7 @@ static void pfpu_start(MilkymistPFPUState *s)
s->gp_regs[GPR_Y] = y;
/* run microcode on this position */
- i = 0;
- while (pfpu_decode_insn(s)) {
- /* decode at most MICROCODE_WORDS instructions */
- if (i++ >= MICROCODE_WORDS) {
- error_report("milkymist_pfpu: too many instructions "
- "executed in microcode. No VECTOUT?");
- break;
- }
- }
+ while (pfpu_decode_insn(s));
/* reset pc for next run */
s->regs[R_PC] = 0;
--
2.3.0
