accel/tcg: Remove unnecessary check on icount_extra in cpu_loop_exec_tb()
In cpu_loop_exec_tb(), we decide whether to look for a TB with exactly insns_left instructions in it using the condition (!cpu->icount_extra && insns_left > 0 && insns_left < tb->icount) The check for icount_extra == 0 is unnecessary, because we just set insns_left = MIN(0xffff, cpu->icount_budget); icount_extra = icount_budget - insns_left; and so icount_extra can only be non-zero if icount_budget > 0xffff and insns_left == 0xffff. But in that case insns_left >= tb->icount because 0xffff is much larger than TCG_MAX_INSNS, so the condition will be false anyway. Remove the unnecessary check, and instead assert: * that we are only going to execute a partial TB here if the icount budget has run out (ie icount_extra == 0) * that the number of insns we're going to execute does fit into the CF_COUNT_MASK Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Reviewed-by: Richard Henderson <richard.henderson@linaro.org> Message-Id: <20210725174405.24568-3-peter.maydell@linaro.org> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
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@ -843,7 +843,9 @@ static inline void cpu_loop_exec_tb(CPUState *cpu, TranslationBlock *tb,
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* execute we need to ensure we find/generate a TB with exactly
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* insns_left instructions in it.
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*/
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if (!cpu->icount_extra && insns_left > 0 && insns_left < tb->icount) {
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if (insns_left > 0 && insns_left < tb->icount) {
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assert(insns_left <= CF_COUNT_MASK);
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assert(cpu->icount_extra == 0);
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cpu->cflags_next_tb = (tb->cflags & ~CF_COUNT_MASK) | insns_left;
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}
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#endif
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